diff --git a/src/utils/SkOffsetPolygon.cpp b/src/utils/SkOffsetPolygon.cpp
index c8ebbeb..bfd12d2 100755
--- a/src/utils/SkOffsetPolygon.cpp
+++ b/src/utils/SkOffsetPolygon.cpp
@@ -8,9 +8,11 @@
 #include "SkOffsetPolygon.h"
 
 #include "SkPointPriv.h"
+#include "SkTArray.h"
 #include "SkTemplates.h"
+#include "SkTDPQueue.h"
 
-struct InsetSegment {
+struct OffsetSegment {
     SkPoint fP0;
     SkPoint fP1;
 };
@@ -95,39 +97,65 @@
 // Compute the intersection 'p' between segments s0 and s1, if any.
 // 's' is the parametric value for the intersection along 's0' & 't' is the same for 's1'.
 // Returns false if there is no intersection.
-static bool compute_intersection(const InsetSegment& s0, const InsetSegment& s1,
+static bool compute_intersection(const OffsetSegment& s0, const OffsetSegment& s1,
                                  SkPoint* p, SkScalar* s, SkScalar* t) {
+    // Common cases for polygon chains -- check if endpoints are touching
+    if (SkPointPriv::EqualsWithinTolerance(s0.fP1, s1.fP0)) {
+        *p = s0.fP1;
+        *s = SK_Scalar1;
+        *t = 0;
+        return true;
+    }
+    if (SkPointPriv::EqualsWithinTolerance(s1.fP1, s0.fP0)) {
+        *p = s1.fP1;
+        *s = 0;
+        *t = SK_Scalar1;
+        return true;
+    }
+
     SkVector v0 = s0.fP1 - s0.fP0;
     SkVector v1 = s1.fP1 - s1.fP0;
-
-    SkScalar perpDot = v0.cross(v1);
-    if (SkScalarNearlyZero(perpDot)) {
-        // segments are parallel
-        // check if endpoints are touching
-        if (SkPointPriv::EqualsWithinTolerance(s0.fP1, s1.fP0)) {
-            *p = s0.fP1;
-            *s = SK_Scalar1;
-            *t = 0;
-            return true;
-        }
-        if (SkPointPriv::EqualsWithinTolerance(s1.fP1, s0.fP0)) {
-            *p = s1.fP1;
-            *s = 0;
-            *t = SK_Scalar1;
-            return true;
-        }
-
-        return false;
-    }
+    // We should have culled coincident points before this
+    SkASSERT(!SkPointPriv::EqualsWithinTolerance(s0.fP0, s0.fP1));
+    SkASSERT(!SkPointPriv::EqualsWithinTolerance(s1.fP0, s1.fP1));
 
     SkVector d = s1.fP0 - s0.fP0;
-    SkScalar localS = d.cross(v1) / perpDot;
-    if (localS < 0 || localS > SK_Scalar1) {
-        return false;
-    }
-    SkScalar localT = d.cross(v0) / perpDot;
-    if (localT < 0 || localT > SK_Scalar1) {
-        return false;
+    SkScalar perpDot = v0.cross(v1);
+    SkScalar localS, localT;
+    if (SkScalarNearlyZero(perpDot)) {
+        // segments are parallel, but not collinear
+        if (!SkScalarNearlyZero(d.dot(d), SK_ScalarNearlyZero*SK_ScalarNearlyZero)) {
+            return false;
+        }
+
+        // project segment1's endpoints onto segment0
+        localS = d.fX / v0.fX;
+        localT = 0;
+        if (localS < 0 || localS > SK_Scalar1) {
+            // the first endpoint doesn't lie on segment0, try the other one
+            SkScalar oldLocalS = localS;
+            localS = (s1.fP1.fX - s0.fP0.fX) / v0.fX;
+            localT = SK_Scalar1;
+            if (localS < 0 || localS > SK_Scalar1) {
+                // it's possible that segment1's interval surrounds segment0
+                // this is false if the params have the same signs, and in that case no collision
+                if (localS*oldLocalS > 0) {
+                    return false;
+                }
+                // otherwise project segment0's endpoint onto segment1 instead
+                localS = 0;
+                localT = -d.fX / v1.fX;
+            }
+        }
+    } else {
+        localS = d.cross(v1) / perpDot;
+        if (localS < 0 || localS > SK_Scalar1) {
+            return false;
+        }
+        localT = d.cross(v0) / perpDot;
+        if (localT < 0 || localT > SK_Scalar1) {
+            return false;
+        }
     }
 
     v0 *= localS;
@@ -138,6 +166,30 @@
     return true;
 }
 
+// computes the line intersection and then the distance to s0's endpoint
+static SkScalar compute_crossing_distance(const OffsetSegment& s0, const OffsetSegment& s1) {
+    SkVector v0 = s0.fP1 - s0.fP0;
+    SkVector v1 = s1.fP1 - s1.fP0;
+
+    SkScalar perpDot = v0.cross(v1);
+    if (SkScalarNearlyZero(perpDot)) {
+        // segments are parallel
+        return SK_ScalarMax;
+    }
+
+    SkVector d = s1.fP0 - s0.fP0;
+    SkScalar localS = d.cross(v1) / perpDot;
+    if (localS < 0) {
+        localS = -localS;
+    } else {
+        localS -= SK_Scalar1;
+    }
+
+    localS *= v0.length();
+
+    return localS;
+}
+
 static bool is_convex(const SkTDArray<SkPoint>& poly) {
     if (poly.count() <= 3) {
         return true;
@@ -162,6 +214,19 @@
     return true;
 }
 
+struct EdgeData {
+    OffsetSegment fInset;
+    SkPoint       fIntersection;
+    SkScalar      fTValue;
+    bool          fValid;
+
+    void init() {
+        fIntersection = fInset.fP0;
+        fTValue = SK_ScalarMin;
+        fValid = true;
+    }
+};
+
 // The objective here is to inset all of the edges by the given distance, and then
 // remove any invalid inset edges by detecting right-hand turns. In a ccw polygon,
 // we should only be making left-hand turns (for cw polygons, we use the winding
@@ -187,13 +252,6 @@
     }
 
     // set up
-    struct EdgeData {
-        InsetSegment fInset;
-        SkPoint      fIntersection;
-        SkScalar     fTValue;
-        bool         fValid;
-    };
-
     SkAutoSTMalloc<64, EdgeData> edgeData(inputPolygonSize);
     for (int i = 0; i < inputPolygonSize; ++i) {
         int j = (i + 1) % inputPolygonSize;
@@ -203,13 +261,13 @@
                          inputPolygonVerts[k])*winding < 0) {
             return false;
         }
-        SkOffsetSegment(inputPolygonVerts[i], inputPolygonVerts[j],
-                        insetDistanceFunc(i), insetDistanceFunc(j),
-                        winding,
-                        &edgeData[i].fInset.fP0, &edgeData[i].fInset.fP1);
-        edgeData[i].fIntersection = edgeData[i].fInset.fP0;
-        edgeData[i].fTValue = SK_ScalarMin;
-        edgeData[i].fValid = true;
+        if (!SkOffsetSegment(inputPolygonVerts[i], inputPolygonVerts[j],
+                             insetDistanceFunc(i), insetDistanceFunc(j),
+                             winding,
+                             &edgeData[i].fInset.fP0, &edgeData[i].fInset.fP1)) {
+            return false;
+        }
+        edgeData[i].init();
     }
 
     int prevIndex = inputPolygonSize - 1;
@@ -294,3 +352,386 @@
 
     return (insetPolygon->count() >= 3 && is_convex(*insetPolygon));
 }
+
+// compute the number of points needed for a circular join when offsetting a  reflex vertex
+static void compute_radial_steps(const SkVector& v1, const SkVector& v2, SkScalar r,
+                                 SkScalar* rotSin, SkScalar* rotCos, int* n) {
+    const SkScalar kRecipPixelsPerArcSegment = 0.25f;
+
+    SkScalar rCos = v1.dot(v2);
+    SkScalar rSin = v1.cross(v2);
+    SkScalar theta = SkScalarATan2(rSin, rCos);
+
+    int steps = SkScalarRoundToInt(SkScalarAbs(r*theta*kRecipPixelsPerArcSegment));
+
+    SkScalar dTheta = theta / steps;
+    *rotSin = SkScalarSinCos(dTheta, rotCos);
+    *n = steps;
+}
+
+// tolerant less-than comparison
+static inline bool nearly_lt(SkScalar a, SkScalar b, SkScalar tolerance = SK_ScalarNearlyZero) {
+    return a < b - tolerance;
+}
+
+// a point is "left" to another if its x coordinate is less, or if equal, its y coordinate
+static bool left(const SkPoint& p0, const SkPoint& p1) {
+    return nearly_lt(p0.fX, p1.fX) ||
+           (SkScalarNearlyEqual(p0.fX, p1.fX) && nearly_lt(p0.fY, p1.fY));
+}
+
+struct Vertex {
+    static bool Left(const Vertex& qv0, const Vertex& qv1) {
+        return left(qv0.fPosition, qv1.fPosition);
+    }
+    // packed to fit into 16 bytes (one cache line)
+    SkPoint  fPosition;
+    uint16_t fIndex;       // index in unsorted polygon
+    uint16_t fPrevIndex;   // indices for previous and next vertex in unsorted polygon
+    uint16_t fNextIndex;
+    uint16_t fFlags;
+};
+
+enum VertexFlags {
+    kPrevLeft_VertexFlag = 0x1,
+    kNextLeft_VertexFlag = 0x2,
+};
+
+struct Edge {
+    // returns true if "this" is above "that"
+    bool above(const Edge& that, SkScalar tolerance = SK_ScalarNearlyZero) {
+        SkASSERT(nearly_lt(this->fSegment.fP0.fX, that.fSegment.fP0.fX, tolerance) ||
+                 SkScalarNearlyEqual(this->fSegment.fP0.fX, that.fSegment.fP0.fX, tolerance));
+        // The idea here is that if the vector between the origins of the two segments (dv)
+        // rotates counterclockwise up to the vector representing the "this" segment (u),
+        // then we know that "this" is above that. If the result is clockwise we say it's below.
+        SkVector dv = that.fSegment.fP0 - this->fSegment.fP0;
+        SkVector u = this->fSegment.fP1 - this->fSegment.fP0;
+        SkScalar cross = dv.cross(u);
+        if (cross > tolerance) {
+            return true;
+        } else if (cross < -tolerance) {
+            return false;
+        }
+        // If the result is 0 then either the two origins are equal or the origin of "that"
+        // lies on dv. So then we try the same for the vector from the tail of "this"
+        // to the head of "that". Again, ccw means "this" is above "that".
+        dv = that.fSegment.fP1 - this->fSegment.fP0;
+        return (dv.cross(u) > tolerance);
+    }
+
+    bool intersect(const Edge& that) const {
+        SkPoint intersection;
+        SkScalar s, t;
+        // check first to see if these edges are neighbors in the polygon
+        if (this->fIndex0 == that.fIndex0 || this->fIndex1 == that.fIndex0 ||
+            this->fIndex0 == that.fIndex1 || this->fIndex1 == that.fIndex1) {
+            return false;
+        }
+        return compute_intersection(this->fSegment, that.fSegment, &intersection, &s, &t);
+    }
+
+    bool operator==(const Edge& that) const {
+        return (this->fIndex0 == that.fIndex0 && this->fIndex1 == that.fIndex1);
+    }
+
+    bool operator!=(const Edge& that) const {
+        return !operator==(that);
+    }
+
+    OffsetSegment fSegment;
+    int32_t fIndex0;   // indices for previous and next vertex
+    int32_t fIndex1;
+};
+
+class EdgeList {
+public:
+    void reserve(int count) { fEdges.reserve(count); }
+
+    bool insert(const Edge& newEdge) {
+        // linear search for now (expected case is very few active edges)
+        int insertIndex = 0;
+        while (insertIndex < fEdges.count() && fEdges[insertIndex].above(newEdge)) {
+            ++insertIndex;
+        }
+        // if we intersect with the existing edge above or below us
+        // then we know this polygon is not simple, so don't insert, just fail
+        if (insertIndex > 0 && newEdge.intersect(fEdges[insertIndex - 1])) {
+            return false;
+        }
+        if (insertIndex < fEdges.count() && newEdge.intersect(fEdges[insertIndex])) {
+            return false;
+        }
+
+        fEdges.push_back();
+        for (int i = fEdges.count() - 1; i > insertIndex; --i) {
+            fEdges[i] = fEdges[i - 1];
+        }
+        fEdges[insertIndex] = newEdge;
+
+        return true;
+    }
+
+    bool remove(const Edge& edge) {
+        SkASSERT(fEdges.count() > 0);
+
+        // linear search for now (expected case is very few active edges)
+        int removeIndex = 0;
+        while (removeIndex < fEdges.count() && fEdges[removeIndex] != edge) {
+            ++removeIndex;
+        }
+        // we'd better find it or something is wrong
+        SkASSERT(removeIndex < fEdges.count());
+
+        // if we intersect with the edge above or below us
+        // then we know this polygon is not simple, so don't remove, just fail
+        if (removeIndex > 0 && fEdges[removeIndex].intersect(fEdges[removeIndex-1])) {
+            return false;
+        }
+        if (removeIndex < fEdges.count()-1) {
+            if (fEdges[removeIndex].intersect(fEdges[removeIndex + 1])) {
+                return false;
+            }
+            // copy over the old entry
+            memmove(&fEdges[removeIndex], &fEdges[removeIndex + 1],
+                    sizeof(Edge)*(fEdges.count() - removeIndex - 1));
+        }
+
+        fEdges.pop_back();
+        return true;
+    }
+
+private:
+    SkSTArray<1, Edge> fEdges;
+};
+
+// Here we implement a sweep line algorithm to determine whether the provided points
+// represent a simple polygon, i.e., the polygon is non-self-intersecting.
+// We first insert the vertices into a priority queue sorting horizontally from left to right.
+// Then as we pop the vertices from the queue we generate events which indicate that an edge
+// should be added or removed from an edge list. If any intersections are detected in the edge
+// list, then we know the polygon is self-intersecting and hence not simple.
+static bool is_simple_polygon(const SkPoint* polygon, int polygonSize) {
+    SkTDPQueue <Vertex, Vertex::Left> vertexQueue;
+    EdgeList sweepLine;
+
+    sweepLine.reserve(polygonSize);
+    for (int i = 0; i < polygonSize; ++i) {
+        Vertex newVertex;
+        newVertex.fPosition = polygon[i];
+        newVertex.fIndex = i;
+        newVertex.fPrevIndex = (i - 1 + polygonSize) % polygonSize;
+        newVertex.fNextIndex = (i + 1) % polygonSize;
+        newVertex.fFlags = 0;
+        if (left(polygon[newVertex.fPrevIndex], polygon[i])) {
+            newVertex.fFlags |= kPrevLeft_VertexFlag;
+        }
+        if (left(polygon[newVertex.fNextIndex], polygon[i])) {
+            newVertex.fFlags |= kNextLeft_VertexFlag;
+        }
+        vertexQueue.insert(newVertex);
+    }
+
+    // pop each vertex from the queue and generate events depending on
+    // where it lies relative to its neighboring edges
+    while (vertexQueue.count() > 0) {
+        const Vertex& v = vertexQueue.peek();
+
+        // check edge to previous vertex
+        if (v.fFlags & kPrevLeft_VertexFlag) {
+            Edge edge{ { polygon[v.fPrevIndex], v.fPosition }, v.fPrevIndex, v.fIndex };
+            if (!sweepLine.remove(edge)) {
+                break;
+            }
+        } else {
+            Edge edge{ { v.fPosition, polygon[v.fPrevIndex] }, v.fIndex, v.fPrevIndex };
+            if (!sweepLine.insert(edge)) {
+                break;
+            }
+        }
+
+        // check edge to next vertex
+        if (v.fFlags & kNextLeft_VertexFlag) {
+            Edge edge{ { polygon[v.fNextIndex], v.fPosition }, v.fNextIndex, v.fIndex };
+            if (!sweepLine.remove(edge)) {
+                break;
+            }
+        } else {
+            Edge edge{ { v.fPosition, polygon[v.fNextIndex] }, v.fIndex, v.fNextIndex };
+            if (!sweepLine.insert(edge)) {
+                break;
+            }
+        }
+
+        vertexQueue.pop();
+    }
+
+    return (vertexQueue.count() == 0);
+}
+
+// TODO: assuming a constant offset here -- do we want to support variable offset?
+bool SkOffsetSimplePolygon(const SkPoint* inputPolygonVerts, int inputPolygonSize,
+                           SkScalar offset, SkTDArray<SkPoint>* offsetPolygon) {
+    if (inputPolygonSize < 3) {
+        return false;
+    }
+
+    if (!is_simple_polygon(inputPolygonVerts, inputPolygonSize)) {
+        return false;
+    }
+
+    // compute area and use sign to determine winding
+    // do initial pass to build normals
+    SkAutoSTMalloc<64, SkVector> normals(inputPolygonSize);
+    SkScalar quadArea = 0;
+    for (int curr = 0; curr < inputPolygonSize; ++curr) {
+        int next = (curr + 1) % inputPolygonSize;
+        SkVector tangent = inputPolygonVerts[next] - inputPolygonVerts[curr];
+        SkVector normal = SkVector::Make(-tangent.fY, tangent.fX);
+        normals[curr] = normal;
+        quadArea += inputPolygonVerts[curr].cross(inputPolygonVerts[next]);
+    }
+    // 1 == ccw, -1 == cw
+    int winding = (quadArea > 0) ? 1 : -1;
+    if (0 == winding) {
+        return false;
+    }
+
+    // resize normals to match offset
+    for (int curr = 0; curr < inputPolygonSize; ++curr) {
+        normals[curr].setLength(winding*offset);
+    }
+
+    // build initial offset edge list
+    SkSTArray<64, EdgeData> edgeData(inputPolygonSize);
+    int prevIndex = inputPolygonSize - 1;
+    int currIndex = 0;
+    int nextIndex = 1;
+    while (currIndex < inputPolygonSize) {
+        int side = compute_side(inputPolygonVerts[prevIndex],
+                                inputPolygonVerts[currIndex],
+                                inputPolygonVerts[nextIndex]);
+
+        // if reflex point, fill in curve
+        if (side*winding*offset < 0) {
+            SkScalar rotSin, rotCos;
+            int numSteps;
+            SkVector prevNormal = normals[prevIndex];
+            compute_radial_steps(prevNormal, normals[currIndex], SkScalarAbs(offset),
+                                 &rotSin, &rotCos, &numSteps);
+            for (int i = 0; i < numSteps - 1; ++i) {
+                SkVector currNormal = SkVector::Make(prevNormal.fX*rotCos - prevNormal.fY*rotSin,
+                                                     prevNormal.fY*rotCos + prevNormal.fX*rotSin);
+                EdgeData& edge = edgeData.push_back();
+                edge.fInset.fP0 = inputPolygonVerts[currIndex] + prevNormal;
+                edge.fInset.fP1 = inputPolygonVerts[currIndex] + currNormal;
+                edge.init();
+                prevNormal = currNormal;
+            }
+            EdgeData& edge = edgeData.push_back();
+            edge.fInset.fP0 = inputPolygonVerts[currIndex] + prevNormal;
+            edge.fInset.fP1 = inputPolygonVerts[currIndex] + normals[currIndex];
+            edge.init();
+        }
+
+        // Add the edge
+        EdgeData& edge = edgeData.push_back();
+        edge.fInset.fP0 = inputPolygonVerts[currIndex] + normals[currIndex];
+        edge.fInset.fP1 = inputPolygonVerts[nextIndex] + normals[currIndex];
+        edge.init();
+
+        prevIndex = currIndex;
+        currIndex++;
+        nextIndex = (nextIndex + 1) % inputPolygonSize;
+    }
+
+    int edgeDataSize = edgeData.count();
+    prevIndex = edgeDataSize - 1;
+    currIndex = 0;
+    int insetVertexCount = edgeDataSize;
+    while (prevIndex != currIndex) {
+        if (!edgeData[prevIndex].fValid) {
+            prevIndex = (prevIndex + edgeDataSize - 1) % edgeDataSize;
+            continue;
+        }
+
+        SkScalar s, t;
+        SkPoint intersection;
+        if (compute_intersection(edgeData[prevIndex].fInset, edgeData[currIndex].fInset,
+                                 &intersection, &s, &t)) {
+            // if new intersection is further back on previous inset from the prior intersection
+            if (s < edgeData[prevIndex].fTValue) {
+                // no point in considering this one again
+                edgeData[prevIndex].fValid = false;
+                --insetVertexCount;
+                // go back one segment
+                prevIndex = (prevIndex + edgeDataSize - 1) % edgeDataSize;
+                // we've already considered this intersection, we're done
+            } else if (edgeData[currIndex].fTValue > SK_ScalarMin &&
+                       SkPointPriv::EqualsWithinTolerance(intersection,
+                                                          edgeData[currIndex].fIntersection,
+                                                          1.0e-6f)) {
+                break;
+            } else {
+                // add intersection
+                edgeData[currIndex].fIntersection = intersection;
+                edgeData[currIndex].fTValue = t;
+
+                // go to next segment
+                prevIndex = currIndex;
+                currIndex = (currIndex + 1) % edgeDataSize;
+            }
+        } else {
+            // If there is no intersection, we want to minimize the distance between
+            // the point where the segment lines cross and the segments themselves.
+            SkScalar prevPrevIndex = (prevIndex + edgeDataSize - 1) % edgeDataSize;
+            SkScalar currNextIndex = (currIndex + 1) % edgeDataSize;
+            SkScalar dist0 = compute_crossing_distance(edgeData[currIndex].fInset,
+                                                       edgeData[prevPrevIndex].fInset);
+            SkScalar dist1 = compute_crossing_distance(edgeData[prevIndex].fInset,
+                                                       edgeData[currNextIndex].fInset);
+            if (dist0 < dist1) {
+                edgeData[prevIndex].fValid = false;
+                prevIndex = prevPrevIndex;
+            } else {
+                edgeData[currIndex].fValid = false;
+                currIndex = currNextIndex;
+            }
+            --insetVertexCount;
+        }
+    }
+
+    // store all the valid intersections that aren't nearly coincident
+    // TODO: look at the main algorithm and see if we can detect these better
+    static constexpr SkScalar kCleanupTolerance = 0.01f;
+
+    offsetPolygon->reset();
+    offsetPolygon->setReserve(insetVertexCount);
+    currIndex = -1;
+    for (int i = 0; i < edgeData.count(); ++i) {
+        if (edgeData[i].fValid && (currIndex == -1 ||
+                                   !SkPointPriv::EqualsWithinTolerance(edgeData[i].fIntersection,
+                                                                       (*offsetPolygon)[currIndex],
+                                                                       kCleanupTolerance))) {
+            *offsetPolygon->push() = edgeData[i].fIntersection;
+            currIndex++;
+        }
+    }
+    // make sure the first and last points aren't coincident
+    if (currIndex >= 1 &&
+        SkPointPriv::EqualsWithinTolerance((*offsetPolygon)[0], (*offsetPolygon)[currIndex],
+                                           kCleanupTolerance)) {
+        offsetPolygon->pop();
+    }
+
+    // compute signed area to check winding (it should be same as the original polygon)
+    quadArea = 0;
+    for (int curr = 0; curr < offsetPolygon->count(); ++curr) {
+        int next = (curr + 1) % offsetPolygon->count();
+        quadArea += (*offsetPolygon)[curr].cross((*offsetPolygon)[next]);
+    }
+
+    return (winding*quadArea > 0 &&
+            is_simple_polygon(offsetPolygon->begin(), offsetPolygon->count()));
+}
+
diff --git a/src/utils/SkOffsetPolygon.h b/src/utils/SkOffsetPolygon.h
index 1d5a19c..a0555ab 100755
--- a/src/utils/SkOffsetPolygon.h
+++ b/src/utils/SkOffsetPolygon.h
@@ -5,8 +5,8 @@
  * found in the LICENSE file.
  */
 
-#ifndef SkInsetConvexPolygon_DEFINED
-#define SkInsetConvexPolygon_DEFINED
+#ifndef SkOffsetPolygon_DEFINED
+#define SkOffsetPolygon_DEFINED
 
 #include <functional>
 
@@ -29,14 +29,27 @@
                           SkTDArray<SkPoint>* insetPolygon);
 
 inline bool SkInsetConvexPolygon(const SkPoint* inputPolygonVerts, int inputPolygonSize,
-                                 SkScalar inset,
-                                 SkTDArray<SkPoint>* insetPolygon) {
+                                 SkScalar inset, SkTDArray<SkPoint>* insetPolygon) {
     return SkInsetConvexPolygon(inputPolygonVerts, inputPolygonSize,
                                 [inset](int) { return inset; },
                                 insetPolygon);
 }
 
 /**
+ * Generates a simple polygon (if possible) that is offset a given distance from the boundary of a
+ * given simple polygon.
+ *
+ * @param inputPolygonVerts  Array of points representing the vertices of the original polygon.
+ * @param inputPolygonSize  Number of vertices in the original polygon.
+ * @param offset  How far we wish to offset the polygon.
+ *                Positive value means inset, negative value means outset.
+ * @param offsetPolgon  The resulting offset polygon, if any.
+ * @return true if an offset simple polygon exists, false otherwise.
+ */
+bool SkOffsetSimplePolygon(const SkPoint* inputPolygonVerts, int inputPolygonSize,
+                           SkScalar offset, SkTDArray<SkPoint>* offsetPolygon);
+
+/**
  * Offset a segment by the given distance at each point.
  * Uses the outer tangents of two circles centered on each endpoint.
  * See: https://en.wikipedia.org/wiki/Tangent_lines_to_circles