diff --git a/src/gpu/GrReducedClip.cpp b/src/gpu/GrReducedClip.cpp
index 251155b..237ea22 100644
--- a/src/gpu/GrReducedClip.cpp
+++ b/src/gpu/GrReducedClip.cpp
@@ -11,322 +11,13 @@
 
 typedef SkClipStack::Element Element;
 
-static GrReducedClip::InitialState reduced_stack_walker(const SkClipStack& stack,
-                                                        const SkRect& queryBounds,
-                                                        const SkIRect& clipIBounds,
-                                                        GrReducedClip::ElementList* result,
-                                                        int32_t* resultGenID,
-                                                        bool* requiresAA) {
-
-    // walk backwards until we get to:
-    //  a) the beginning
-    //  b) an operation that is known to make the bounds all inside/outside
-    //  c) a replace operation
-
-    enum class InitialTriState {
-        kUnknown = -1,
-        kAllIn = (int)GrReducedClip::InitialState::kAllIn,
-        kAllOut = (int)GrReducedClip::InitialState::kAllOut
-    } initialState = InitialTriState::kUnknown;
-
-    // During our backwards walk, track whether we've seen ops that either grow or shrink the clip.
-    // TODO: track these per saved clip so that we can consider them on the forward pass.
-    bool embiggens = false;
-    bool emsmallens = false;
-
-    // We use a slightly relaxed set of query bounds for element containment tests. This is to
-    // account for floating point rounding error that may have occurred during coord transforms.
-    SkRect relaxedQueryBounds = queryBounds.makeInset(GrClip::kBoundsTolerance,
-                                                      GrClip::kBoundsTolerance);
-
-    SkClipStack::Iter iter(stack, SkClipStack::Iter::kTop_IterStart);
-    int numAAElements = 0;
-    while (InitialTriState::kUnknown == initialState) {
-        const Element* element = iter.prev();
-        if (nullptr == element) {
-            initialState = InitialTriState::kAllIn;
-            break;
-        }
-        if (SkClipStack::kEmptyGenID == element->getGenID()) {
-            initialState = InitialTriState::kAllOut;
-            break;
-        }
-        if (SkClipStack::kWideOpenGenID == element->getGenID()) {
-            initialState = InitialTriState::kAllIn;
-            break;
-        }
-
-        bool skippable = false;
-        bool isFlip = false; // does this op just flip the in/out state of every point in the bounds
-
-        switch (element->getOp()) {
-            case SkRegion::kDifference_Op:
-                // check if the shape subtracted either contains the entire bounds (and makes
-                // the clip empty) or is outside the bounds and therefore can be skipped.
-                if (element->isInverseFilled()) {
-                    if (element->contains(relaxedQueryBounds)) {
-                        skippable = true;
-                    } else if (GrClip::IsOutsideClip(element->getBounds(), queryBounds)) {
-                        initialState = InitialTriState::kAllOut;
-                        skippable = true;
-                    }
-                } else {
-                    if (element->contains(relaxedQueryBounds)) {
-                        initialState = InitialTriState::kAllOut;
-                        skippable = true;
-                    } else if (GrClip::IsOutsideClip(element->getBounds(), queryBounds)) {
-                        skippable = true;
-                    }
-                }
-                if (!skippable) {
-                    emsmallens = true;
-                }
-                break;
-            case SkRegion::kIntersect_Op:
-                // check if the shape intersected contains the entire bounds and therefore can
-                // be skipped or it is outside the entire bounds and therefore makes the clip
-                // empty.
-                if (element->isInverseFilled()) {
-                    if (element->contains(relaxedQueryBounds)) {
-                        initialState = InitialTriState::kAllOut;
-                        skippable = true;
-                    } else if (GrClip::IsOutsideClip(element->getBounds(), queryBounds)) {
-                        skippable = true;
-                    }
-                } else {
-                    if (element->contains(relaxedQueryBounds)) {
-                        skippable = true;
-                    } else if (GrClip::IsOutsideClip(element->getBounds(), queryBounds)) {
-                        initialState = InitialTriState::kAllOut;
-                        skippable = true;
-                    }
-                }
-                if (!skippable) {
-                    emsmallens = true;
-                }
-                break;
-            case SkRegion::kUnion_Op:
-                // If the union-ed shape contains the entire bounds then after this element
-                // the bounds is entirely inside the clip. If the union-ed shape is outside the
-                // bounds then this op can be skipped.
-                if (element->isInverseFilled()) {
-                    if (element->contains(relaxedQueryBounds)) {
-                        skippable = true;
-                    } else if (GrClip::IsOutsideClip(element->getBounds(), queryBounds)) {
-                        initialState = InitialTriState::kAllIn;
-                        skippable = true;
-                    }
-                } else {
-                    if (element->contains(relaxedQueryBounds)) {
-                        initialState = InitialTriState::kAllIn;
-                        skippable = true;
-                    } else if (GrClip::IsOutsideClip(element->getBounds(), queryBounds)) {
-                        skippable = true;
-                    }
-                }
-                if (!skippable) {
-                    embiggens = true;
-                }
-                break;
-            case SkRegion::kXOR_Op:
-                // If the bounds is entirely inside the shape being xor-ed then the effect is
-                // to flip the inside/outside state of every point in the bounds. We may be
-                // able to take advantage of this in the forward pass. If the xor-ed shape
-                // doesn't intersect the bounds then it can be skipped.
-                if (element->isInverseFilled()) {
-                    if (element->contains(relaxedQueryBounds)) {
-                        skippable = true;
-                    } else if (GrClip::IsOutsideClip(element->getBounds(), queryBounds)) {
-                        isFlip = true;
-                    }
-                } else {
-                    if (element->contains(relaxedQueryBounds)) {
-                        isFlip = true;
-                    } else if (GrClip::IsOutsideClip(element->getBounds(), queryBounds)) {
-                        skippable = true;
-                    }
-                }
-                if (!skippable) {
-                    emsmallens = embiggens = true;
-                }
-                break;
-            case SkRegion::kReverseDifference_Op:
-                // When the bounds is entirely within the rev-diff shape then this behaves like xor
-                // and reverses every point inside the bounds. If the shape is completely outside
-                // the bounds then we know after this element is applied that the bounds will be
-                // all outside the current clip.B
-                if (element->isInverseFilled()) {
-                    if (element->contains(relaxedQueryBounds)) {
-                        initialState = InitialTriState::kAllOut;
-                        skippable = true;
-                    } else if (GrClip::IsOutsideClip(element->getBounds(), queryBounds)) {
-                        isFlip = true;
-                    }
-                } else {
-                    if (element->contains(relaxedQueryBounds)) {
-                        isFlip = true;
-                    } else if (GrClip::IsOutsideClip(element->getBounds(), queryBounds)) {
-                        initialState = InitialTriState::kAllOut;
-                        skippable = true;
-                    }
-                }
-                if (!skippable) {
-                    emsmallens = embiggens = true;
-                }
-                break;
-
-            case SkRegion::kReplace_Op:
-                // Replace will always terminate our walk. We will either begin the forward walk
-                // at the replace op or detect here than the shape is either completely inside
-                // or completely outside the bounds. In this latter case it can be skipped by
-                // setting the correct value for initialState.
-                if (element->isInverseFilled()) {
-                    if (element->contains(relaxedQueryBounds)) {
-                        initialState = InitialTriState::kAllOut;
-                        skippable = true;
-                    } else if (GrClip::IsOutsideClip(element->getBounds(), queryBounds)) {
-                        initialState = InitialTriState::kAllIn;
-                        skippable = true;
-                    }
-                } else {
-                    if (element->contains(relaxedQueryBounds)) {
-                        initialState = InitialTriState::kAllIn;
-                        skippable = true;
-                    } else if (GrClip::IsOutsideClip(element->getBounds(), queryBounds)) {
-                        initialState = InitialTriState::kAllOut;
-                        skippable = true;
-                    }
-                }
-                if (!skippable) {
-                    initialState = InitialTriState::kAllOut;
-                    embiggens = emsmallens = true;
-                }
-                break;
-            default:
-                SkDEBUGFAIL("Unexpected op.");
-                break;
-        }
-        if (!skippable) {
-            if (0 == result->count()) {
-                // This will be the last element. Record the stricter genID.
-                *resultGenID = element->getGenID();
-            }
-
-            // if it is a flip, change it to a bounds-filling rect
-            if (isFlip) {
-                SkASSERT(SkRegion::kXOR_Op == element->getOp() ||
-                         SkRegion::kReverseDifference_Op == element->getOp());
-                result->addToHead(SkRect::Make(clipIBounds), SkRegion::kReverseDifference_Op,
-                                  false);
-            } else {
-                Element* newElement = result->addToHead(*element);
-                if (newElement->isAA()) {
-                    ++numAAElements;
-                }
-                // Intersecting an inverse shape is the same as differencing the non-inverse shape.
-                // Replacing with an inverse shape is the same as setting initialState=kAllIn and
-                // differencing the non-inverse shape.
-                bool isReplace = SkRegion::kReplace_Op == newElement->getOp();
-                if (newElement->isInverseFilled() &&
-                    (SkRegion::kIntersect_Op == newElement->getOp() || isReplace)) {
-                    newElement->invertShapeFillType();
-                    newElement->setOp(SkRegion::kDifference_Op);
-                    if (isReplace) {
-                        SkASSERT(InitialTriState::kAllOut == initialState);
-                        initialState = InitialTriState::kAllIn;
-                    }
-                }
-            }
-        }
-    }
-
-    if ((InitialTriState::kAllOut == initialState && !embiggens) ||
-        (InitialTriState::kAllIn == initialState && !emsmallens)) {
-        result->reset();
-        numAAElements = 0;
-    } else {
-        Element* element = result->headIter().get();
-        while (element) {
-            bool skippable = false;
-            switch (element->getOp()) {
-                case SkRegion::kDifference_Op:
-                    // subtracting from the empty set yields the empty set.
-                    skippable = InitialTriState::kAllOut == initialState;
-                    break;
-                case SkRegion::kIntersect_Op:
-                    // intersecting with the empty set yields the empty set
-                    if (InitialTriState::kAllOut == initialState) {
-                        skippable = true;
-                    } else {
-                        // We can clear to zero and then simply draw the clip element.
-                        initialState = InitialTriState::kAllOut;
-                        element->setOp(SkRegion::kReplace_Op);
-                    }
-                    break;
-                case SkRegion::kUnion_Op:
-                    if (InitialTriState::kAllIn == initialState) {
-                        // unioning the infinite plane with anything is a no-op.
-                        skippable = true;
-                    } else {
-                        // unioning the empty set with a shape is the shape.
-                        element->setOp(SkRegion::kReplace_Op);
-                    }
-                    break;
-                case SkRegion::kXOR_Op:
-                    if (InitialTriState::kAllOut == initialState) {
-                        // xor could be changed to diff in the kAllIn case, not sure it's a win.
-                        element->setOp(SkRegion::kReplace_Op);
-                    }
-                    break;
-                case SkRegion::kReverseDifference_Op:
-                    if (InitialTriState::kAllIn == initialState) {
-                        // subtracting the whole plane will yield the empty set.
-                        skippable = true;
-                        initialState = InitialTriState::kAllOut;
-                    } else {
-                        // this picks up flips inserted in the backwards pass.
-                        skippable = element->isInverseFilled() ?
-                            GrClip::IsOutsideClip(element->getBounds(), queryBounds) :
-                            element->contains(relaxedQueryBounds);
-                        if (skippable) {
-                            initialState = InitialTriState::kAllIn;
-                        } else {
-                            element->setOp(SkRegion::kReplace_Op);
-                        }
-                    }
-                    break;
-                case SkRegion::kReplace_Op:
-                    skippable = false; // we would have skipped it in the backwards walk if we
-                                       // could've.
-                    break;
-                default:
-                    SkDEBUGFAIL("Unexpected op.");
-                    break;
-            }
-            if (!skippable) {
-                break;
-            } else {
-                if (element->isAA()) {
-                    --numAAElements;
-                }
-                result->popHead();
-                element = result->headIter().get();
-            }
-        }
-    }
-    *requiresAA = numAAElements > 0;
-
-    SkASSERT(InitialTriState::kUnknown != initialState);
-    return static_cast<GrReducedClip::InitialState>(initialState);
-}
-
-/*
-There are plenty of optimizations that could be added here. Maybe flips could be folded into
-earlier operations. Or would inserting flips and reversing earlier ops ever be a win? Perhaps
-for the case where the bounds are kInsideOut_BoundsType. We could restrict earlier operations
-based on later intersect operations, and perhaps remove intersect-rects. We could optionally
-take a rect in case the caller knows a bound on what is to be drawn through this clip.
-*/
+/**
+ * There are plenty of optimizations that could be added here. Maybe flips could be folded into
+ * earlier operations. Or would inserting flips and reversing earlier ops ever be a win? Perhaps
+ * for the case where the bounds are kInsideOut_BoundsType. We could restrict earlier operations
+ * based on later intersect operations, and perhaps remove intersect-rects. We could optionally
+ * take a rect in case the caller knows a bound on what is to be drawn through this clip.
+ */
 GrReducedClip::GrReducedClip(const SkClipStack& stack, const SkRect& queryBounds) {
     SkASSERT(!queryBounds.isEmpty());
     fHasIBounds = false;
@@ -393,6 +84,340 @@
 
     // Now that we have determined the bounds to use and filtered out the trivial cases, call the
     // helper that actually walks the stack.
-    fInitialState = reduced_stack_walker(stack, tighterQuery, fIBounds, &fElements, &fElementsGenID,
-                                         &fRequiresAA);
+    this->walkStack(stack, tighterQuery);
+}
+
+void GrReducedClip::walkStack(const SkClipStack& stack, const SkRect& queryBounds) {
+    // walk backwards until we get to:
+    //  a) the beginning
+    //  b) an operation that is known to make the bounds all inside/outside
+    //  c) a replace operation
+
+    enum class InitialTriState {
+        kUnknown = -1,
+        kAllIn = (int)GrReducedClip::InitialState::kAllIn,
+        kAllOut = (int)GrReducedClip::InitialState::kAllOut
+    } initialTriState = InitialTriState::kUnknown;
+
+    // During our backwards walk, track whether we've seen ops that either grow or shrink the clip.
+    // TODO: track these per saved clip so that we can consider them on the forward pass.
+    bool embiggens = false;
+    bool emsmallens = false;
+
+    // We use a slightly relaxed set of query bounds for element containment tests. This is to
+    // account for floating point rounding error that may have occurred during coord transforms.
+    SkRect relaxedQueryBounds = queryBounds.makeInset(GrClip::kBoundsTolerance,
+                                                      GrClip::kBoundsTolerance);
+
+    SkClipStack::Iter iter(stack, SkClipStack::Iter::kTop_IterStart);
+    int numAAElements = 0;
+    while (InitialTriState::kUnknown == initialTriState) {
+        const Element* element = iter.prev();
+        if (nullptr == element) {
+            initialTriState = InitialTriState::kAllIn;
+            break;
+        }
+        if (SkClipStack::kEmptyGenID == element->getGenID()) {
+            initialTriState = InitialTriState::kAllOut;
+            break;
+        }
+        if (SkClipStack::kWideOpenGenID == element->getGenID()) {
+            initialTriState = InitialTriState::kAllIn;
+            break;
+        }
+
+        bool skippable = false;
+        bool isFlip = false; // does this op just flip the in/out state of every point in the bounds
+
+        switch (element->getOp()) {
+            case SkRegion::kDifference_Op:
+                // check if the shape subtracted either contains the entire bounds (and makes
+                // the clip empty) or is outside the bounds and therefore can be skipped.
+                if (element->isInverseFilled()) {
+                    if (element->contains(relaxedQueryBounds)) {
+                        skippable = true;
+                    } else if (GrClip::IsOutsideClip(element->getBounds(), queryBounds)) {
+                        initialTriState = InitialTriState::kAllOut;
+                        skippable = true;
+                    }
+                } else {
+                    if (element->contains(relaxedQueryBounds)) {
+                        initialTriState = InitialTriState::kAllOut;
+                        skippable = true;
+                    } else if (GrClip::IsOutsideClip(element->getBounds(), queryBounds)) {
+                        skippable = true;
+                    }
+                }
+                if (!skippable) {
+                    emsmallens = true;
+                }
+                break;
+            case SkRegion::kIntersect_Op:
+                // check if the shape intersected contains the entire bounds and therefore can
+                // be skipped or it is outside the entire bounds and therefore makes the clip
+                // empty.
+                if (element->isInverseFilled()) {
+                    if (element->contains(relaxedQueryBounds)) {
+                        initialTriState = InitialTriState::kAllOut;
+                        skippable = true;
+                    } else if (GrClip::IsOutsideClip(element->getBounds(), queryBounds)) {
+                        skippable = true;
+                    }
+                } else {
+                    if (element->contains(relaxedQueryBounds)) {
+                        skippable = true;
+                    } else if (GrClip::IsOutsideClip(element->getBounds(), queryBounds)) {
+                        initialTriState = InitialTriState::kAllOut;
+                        skippable = true;
+                    } else if (!embiggens && !element->isAA() &&
+                               Element::kRect_Type == element->getType()) {
+                        // fIBounds and queryBounds have already acccounted for this element via
+                        // clip stack bounds; here we just apply the non-aa rounding effect.
+                        SkIRect nonaaRect;
+                        element->getRect().round(&nonaaRect);
+                        if (!this->intersectIBounds(nonaaRect)) {
+                            return;
+                        }
+                        skippable = true;
+                    }
+                }
+                if (!skippable) {
+                    emsmallens = true;
+                }
+                break;
+            case SkRegion::kUnion_Op:
+                // If the union-ed shape contains the entire bounds then after this element
+                // the bounds is entirely inside the clip. If the union-ed shape is outside the
+                // bounds then this op can be skipped.
+                if (element->isInverseFilled()) {
+                    if (element->contains(relaxedQueryBounds)) {
+                        skippable = true;
+                    } else if (GrClip::IsOutsideClip(element->getBounds(), queryBounds)) {
+                        initialTriState = InitialTriState::kAllIn;
+                        skippable = true;
+                    }
+                } else {
+                    if (element->contains(relaxedQueryBounds)) {
+                        initialTriState = InitialTriState::kAllIn;
+                        skippable = true;
+                    } else if (GrClip::IsOutsideClip(element->getBounds(), queryBounds)) {
+                        skippable = true;
+                    }
+                }
+                if (!skippable) {
+                    embiggens = true;
+                }
+                break;
+            case SkRegion::kXOR_Op:
+                // If the bounds is entirely inside the shape being xor-ed then the effect is
+                // to flip the inside/outside state of every point in the bounds. We may be
+                // able to take advantage of this in the forward pass. If the xor-ed shape
+                // doesn't intersect the bounds then it can be skipped.
+                if (element->isInverseFilled()) {
+                    if (element->contains(relaxedQueryBounds)) {
+                        skippable = true;
+                    } else if (GrClip::IsOutsideClip(element->getBounds(), queryBounds)) {
+                        isFlip = true;
+                    }
+                } else {
+                    if (element->contains(relaxedQueryBounds)) {
+                        isFlip = true;
+                    } else if (GrClip::IsOutsideClip(element->getBounds(), queryBounds)) {
+                        skippable = true;
+                    }
+                }
+                if (!skippable) {
+                    emsmallens = embiggens = true;
+                }
+                break;
+            case SkRegion::kReverseDifference_Op:
+                // When the bounds is entirely within the rev-diff shape then this behaves like xor
+                // and reverses every point inside the bounds. If the shape is completely outside
+                // the bounds then we know after this element is applied that the bounds will be
+                // all outside the current clip.B
+                if (element->isInverseFilled()) {
+                    if (element->contains(relaxedQueryBounds)) {
+                        initialTriState = InitialTriState::kAllOut;
+                        skippable = true;
+                    } else if (GrClip::IsOutsideClip(element->getBounds(), queryBounds)) {
+                        isFlip = true;
+                    }
+                } else {
+                    if (element->contains(relaxedQueryBounds)) {
+                        isFlip = true;
+                    } else if (GrClip::IsOutsideClip(element->getBounds(), queryBounds)) {
+                        initialTriState = InitialTriState::kAllOut;
+                        skippable = true;
+                    }
+                }
+                if (!skippable) {
+                    emsmallens = embiggens = true;
+                }
+                break;
+
+            case SkRegion::kReplace_Op:
+                // Replace will always terminate our walk. We will either begin the forward walk
+                // at the replace op or detect here than the shape is either completely inside
+                // or completely outside the bounds. In this latter case it can be skipped by
+                // setting the correct value for initialTriState.
+                if (element->isInverseFilled()) {
+                    if (element->contains(relaxedQueryBounds)) {
+                        initialTriState = InitialTriState::kAllOut;
+                        skippable = true;
+                    } else if (GrClip::IsOutsideClip(element->getBounds(), queryBounds)) {
+                        initialTriState = InitialTriState::kAllIn;
+                        skippable = true;
+                    }
+                } else {
+                    if (element->contains(relaxedQueryBounds)) {
+                        initialTriState = InitialTriState::kAllIn;
+                        skippable = true;
+                    } else if (GrClip::IsOutsideClip(element->getBounds(), queryBounds)) {
+                        initialTriState = InitialTriState::kAllOut;
+                        skippable = true;
+                    } else if (!embiggens && !element->isAA() &&
+                               Element::kRect_Type == element->getType()) {
+                        // fIBounds and queryBounds have already acccounted for this element via
+                        // clip stack bounds; here we just apply the non-aa rounding effect.
+                        SkIRect nonaaRect;
+                        element->getRect().round(&nonaaRect);
+                        if (!this->intersectIBounds(nonaaRect)) {
+                            return;
+                        }
+                        initialTriState = InitialTriState::kAllIn;
+                        skippable = true;
+                    }
+                }
+                if (!skippable) {
+                    initialTriState = InitialTriState::kAllOut;
+                    embiggens = emsmallens = true;
+                }
+                break;
+            default:
+                SkDEBUGFAIL("Unexpected op.");
+                break;
+        }
+        if (!skippable) {
+            if (0 == fElements.count()) {
+                // This will be the last element. Record the stricter genID.
+                fElementsGenID = element->getGenID();
+            }
+
+            // if it is a flip, change it to a bounds-filling rect
+            if (isFlip) {
+                SkASSERT(SkRegion::kXOR_Op == element->getOp() ||
+                         SkRegion::kReverseDifference_Op == element->getOp());
+                fElements.addToHead(SkRect::Make(fIBounds), SkRegion::kReverseDifference_Op, false);
+            } else {
+                Element* newElement = fElements.addToHead(*element);
+                if (newElement->isAA()) {
+                    ++numAAElements;
+                }
+                // Intersecting an inverse shape is the same as differencing the non-inverse shape.
+                // Replacing with an inverse shape is the same as setting initialState=kAllIn and
+                // differencing the non-inverse shape.
+                bool isReplace = SkRegion::kReplace_Op == newElement->getOp();
+                if (newElement->isInverseFilled() &&
+                    (SkRegion::kIntersect_Op == newElement->getOp() || isReplace)) {
+                    newElement->invertShapeFillType();
+                    newElement->setOp(SkRegion::kDifference_Op);
+                    if (isReplace) {
+                        SkASSERT(InitialTriState::kAllOut == initialTriState);
+                        initialTriState = InitialTriState::kAllIn;
+                    }
+                }
+            }
+        }
+    }
+
+    if ((InitialTriState::kAllOut == initialTriState && !embiggens) ||
+        (InitialTriState::kAllIn == initialTriState && !emsmallens)) {
+        fElements.reset();
+        numAAElements = 0;
+    } else {
+        Element* element = fElements.headIter().get();
+        while (element) {
+            bool skippable = false;
+            switch (element->getOp()) {
+                case SkRegion::kDifference_Op:
+                    // subtracting from the empty set yields the empty set.
+                    skippable = InitialTriState::kAllOut == initialTriState;
+                    break;
+                case SkRegion::kIntersect_Op:
+                    // intersecting with the empty set yields the empty set
+                    if (InitialTriState::kAllOut == initialTriState) {
+                        skippable = true;
+                    } else {
+                        // We can clear to zero and then simply draw the clip element.
+                        initialTriState = InitialTriState::kAllOut;
+                        element->setOp(SkRegion::kReplace_Op);
+                    }
+                    break;
+                case SkRegion::kUnion_Op:
+                    if (InitialTriState::kAllIn == initialTriState) {
+                        // unioning the infinite plane with anything is a no-op.
+                        skippable = true;
+                    } else {
+                        // unioning the empty set with a shape is the shape.
+                        element->setOp(SkRegion::kReplace_Op);
+                    }
+                    break;
+                case SkRegion::kXOR_Op:
+                    if (InitialTriState::kAllOut == initialTriState) {
+                        // xor could be changed to diff in the kAllIn case, not sure it's a win.
+                        element->setOp(SkRegion::kReplace_Op);
+                    }
+                    break;
+                case SkRegion::kReverseDifference_Op:
+                    if (InitialTriState::kAllIn == initialTriState) {
+                        // subtracting the whole plane will yield the empty set.
+                        skippable = true;
+                        initialTriState = InitialTriState::kAllOut;
+                    } else {
+                        // this picks up flips inserted in the backwards pass.
+                        skippable = element->isInverseFilled() ?
+                            GrClip::IsOutsideClip(element->getBounds(), queryBounds) :
+                            element->contains(relaxedQueryBounds);
+                        if (skippable) {
+                            initialTriState = InitialTriState::kAllIn;
+                        } else {
+                            element->setOp(SkRegion::kReplace_Op);
+                        }
+                    }
+                    break;
+                case SkRegion::kReplace_Op:
+                    skippable = false; // we would have skipped it in the backwards walk if we
+                                       // could've.
+                    break;
+                default:
+                    SkDEBUGFAIL("Unexpected op.");
+                    break;
+            }
+            if (!skippable) {
+                break;
+            } else {
+                if (element->isAA()) {
+                    --numAAElements;
+                }
+                fElements.popHead();
+                element = fElements.headIter().get();
+            }
+        }
+    }
+    fRequiresAA = numAAElements > 0;
+
+    SkASSERT(InitialTriState::kUnknown != initialTriState);
+    fInitialState = static_cast<GrReducedClip::InitialState>(initialTriState);
+}
+
+inline bool GrReducedClip::intersectIBounds(const SkIRect& irect) {
+    SkASSERT(fHasIBounds);
+    if (!fIBounds.intersect(irect)) {
+        fHasIBounds = false;
+        fElements.reset();
+        fRequiresAA = false;
+        fInitialState = InitialState::kAllOut;
+        return false;
+    }
+    return true;
 }
diff --git a/src/gpu/GrReducedClip.h b/src/gpu/GrReducedClip.h
index a867483..c3f94a0 100644
--- a/src/gpu/GrReducedClip.h
+++ b/src/gpu/GrReducedClip.h
@@ -61,6 +61,9 @@
     InitialState initialState() const { return fInitialState; }
 
 private:
+    void walkStack(const SkClipStack&, const SkRect& queryBounds);
+    bool intersectIBounds(const SkIRect&);
+
     SkIRect        fIBounds;
     bool           fHasIBounds;
     ElementList    fElements;