Reland "Simplify GrRTC::clean APIs"

This reverts commit 4730f29993783fc9e96e45098d7e708fe08f1f26.

Reason for revert: Fix WIP

Original change's description:
> Revert "Simplify GrRTC::clean APIs"
> 
> This reverts commit 6cbd7c2e57af9c499f7e99feb215b890fdd3a10a.
> 
> Reason for revert: mac/generated files failures
> 
> Original change's description:
> > Simplify GrRTC::clean APIs
> > 
> > The CanClearFullscreen enum type is removed. Most usages of clear() had
> > kYes because a null scissor rect was provided, or had kNo because the
> > scissor was really critical to the behavior. A few places did provide a
> > scissor and kYes (e.g. for initializing the target).
> > 
> > To simplify this, the public GrRTC has two variants of clear(). One with
> > only a color (for fullscreen clears), and one with a rect for partial
> > clears. The private API also adds a clearAtLeast() function that replaces
> > the several cases where we'd have a scissor but could expand to fullscreen.
> > 
> > I find the current control flow in internalClear() to be hard to
> > follow (albeit I was the one to make it that way...), but later CLs
> > will improve it.
> > 
> > Bug: skia:10205
> > Change-Id: I87cf8d688c58fbe58ee854fbc4ffe22482d969c6
> > Reviewed-on: https://skia-review.googlesource.com/c/skia/+/290256
> > Reviewed-by: Brian Salomon <bsalomon@google.com>
> > Commit-Queue: Michael Ludwig <michaelludwig@google.com>
> 
> TBR=bsalomon@google.com,csmartdalton@google.com,michaelludwig@google.com
> 
> Change-Id: I7131df6f5323f4f9c120cbcfd9bc57e627e2eb65
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: skia:10205
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/291842
> Reviewed-by: Michael Ludwig <michaelludwig@google.com>
> Commit-Queue: Michael Ludwig <michaelludwig@google.com>

# Not skipping CQ checks because this is a reland.

Bug: skia:10205
Change-Id: Id5db153d7c2500279cca8478818b66f67a53e143
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/291844
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
diff --git a/src/gpu/GrRenderTargetContext.cpp b/src/gpu/GrRenderTargetContext.cpp
index cc53910..24755d1 100644
--- a/src/gpu/GrRenderTargetContext.cpp
+++ b/src/gpu/GrRenderTargetContext.cpp
@@ -479,32 +479,6 @@
     this->getOpsTask()->discard();
 }
 
-void GrRenderTargetContext::clear(const SkIRect* rect,
-                                  const SkPMColor4f& color,
-                                  CanClearFullscreen canClearFullscreen) {
-    ASSERT_SINGLE_OWNER
-    RETURN_IF_ABANDONED
-    SkDEBUGCODE(this->validate();)
-    GR_CREATE_TRACE_MARKER_CONTEXT("GrRenderTargetContext", "clear", fContext);
-
-    AutoCheckFlush acf(this->drawingManager());
-    this->internalClear(rect ? GrFixedClip(*rect) : GrFixedClip::Disabled(), color,
-                        canClearFullscreen);
-}
-
-void GrRenderTargetContextPriv::clear(const GrFixedClip& clip,
-                                      const SkPMColor4f& color,
-                                      CanClearFullscreen canClearFullscreen) {
-    ASSERT_SINGLE_OWNER_PRIV
-    RETURN_IF_ABANDONED_PRIV
-    SkDEBUGCODE(fRenderTargetContext->validate();)
-    GR_CREATE_TRACE_MARKER_CONTEXT("GrRenderTargetContextPriv", "clear",
-                                   fRenderTargetContext->fContext);
-
-    AutoCheckFlush acf(fRenderTargetContext->drawingManager());
-    fRenderTargetContext->internalClear(clip, color, canClearFullscreen);
-}
-
 static void clear_to_grpaint(const SkPMColor4f& color, GrPaint* paint) {
     paint->setColor4f(color);
     if (color.isOpaque()) {
@@ -517,19 +491,39 @@
     }
 }
 
-void GrRenderTargetContext::internalClear(const GrFixedClip& clip,
+// NOTE: We currently pass the premul color unmodified to the gpu, since we assume the GrRTC has a
+// premul alpha type. If we ever support different alpha type render targets, this function should
+// transform the color as appropriate.
+void GrRenderTargetContext::internalClear(const SkIRect* scissor,
                                           const SkPMColor4f& color,
-                                          CanClearFullscreen canClearFullscreen) {
-    bool isFull = false;
-    if (!clip.hasWindowRectangles()) {
-        // TODO: wrt the shouldInitializeTextures path, it would be more performant to
-        // only clear the entire target if we knew it had not been cleared before. As
-        // is this could end up doing a lot of redundant clears.
-        isFull = !clip.scissorEnabled() ||
-                 (CanClearFullscreen::kYes == canClearFullscreen &&
-                  (this->caps()->preferFullscreenClears() || this->caps()->shouldInitializeTextures())) ||
-                 clip.scissorRect().contains(SkIRect::MakeWH(this->width(), this->height()));
+                                          bool upgradePartialToFull) {
+    ASSERT_SINGLE_OWNER
+    RETURN_IF_ABANDONED
+    SkDEBUGCODE(this->validate();)
+    GR_CREATE_TRACE_MARKER_CONTEXT("GrRenderTargetContext", "clear", fContext);
+
+    // The clear will be fullscreen if no scissor is provided, or if the scissor is larger than
+    // the logical bounds of the render target, or if the special flag was provided that allows
+    // partial clears to upgrade to full (because it's a scratch resource and the caller knows
+    // anything outside the scissor doesn't matter, but if full screen clears aren't free, then
+    // the scissor is still provided so that fewer pixels are written to).
+    // TODO: wrt the shouldInitializeTextures path, it would be more performant to
+    // only clear the entire target if we knew it had not been cleared before. As
+    // is this could end up doing a lot of redundant clears.
+    GrScissorState scissorState;
+    if (scissor) {
+        // TODO(michaelludwig) - This will get simpler when GrScissorState knows the device dims
+        scissorState.set(*scissor);
+        if (!scissorState.intersect(SkIRect::MakeWH(this->width(), this->height()))) {
+            // The clear is offscreen, so skip it (normally this would be handled by addDrawOp,
+            // except clear ops are not draw ops).
+            return;
+        }
     }
+    bool isFull = !scissorState.enabled() ||
+                  scissorState.rect().contains(SkIRect::MakeWH(this->width(), this->height())) ||
+                  (upgradePartialToFull && (this->caps()->preferFullscreenClears() ||
+                   this->caps()->shouldInitializeTextures()));
 
     if (isFull) {
         GrOpsTask* opsTask = this->getOpsTask();
@@ -554,20 +548,19 @@
                             GrFillRectOp::MakeNonAARect(fContext, std::move(paint), SkMatrix::I(),
                                                         rtRect));
         } else {
-            this->addOp(GrClearOp::Make(
-                    fContext, SkIRect::MakeEmpty(), color, /* fullscreen */ true));
+            this->addOp(GrClearOp::Make(fContext, GrScissorState(), color, this->asSurfaceProxy()));
         }
     } else {
-        if (this->caps()->performPartialClearsAsDraws() || clip.hasWindowRectangles()) {
+        if (this->caps()->performPartialClearsAsDraws()) {
             // performPartialClearsAsDraws() also returns true if any clear has to be a draw.
             GrPaint paint;
             clear_to_grpaint(color, &paint);
 
-            this->addDrawOp(clip,
+            this->addDrawOp(GrFixedClip::Disabled(),
                             GrFillRectOp::MakeNonAARect(fContext, std::move(paint), SkMatrix::I(),
-                                                        SkRect::Make(clip.scissorRect())));
+                                                        SkRect::Make(scissorState.rect())));
         } else {
-            std::unique_ptr<GrOp> op(GrClearOp::Make(fContext, clip.scissorState(), color,
+            std::unique_ptr<GrOp> op(GrClearOp::Make(fContext, scissorState, color,
                                                      this->asSurfaceProxy()));
             // This version of the clear op factory can return null if the clip doesn't intersect
             // with the surface proxy's boundary
@@ -717,14 +710,14 @@
                     drawBounds = quad->fDevice.bounds();
                     if (drawBounds.contains(rtRect)) {
                         // Fullscreen clear
-                        this->clear(nullptr, *constColor, CanClearFullscreen::kYes);
+                        this->clear(*constColor);
                         return QuadOptimization::kSubmitted;
                     } else if (GrClip::IsPixelAligned(drawBounds) &&
                                drawBounds.width() > 256 && drawBounds.height() > 256) {
                         // Scissor + clear (round shouldn't do anything since we are pixel aligned)
                         SkIRect scissorRect;
                         drawBounds.round(&scissorRect);
-                        this->clear(&scissorRect, *constColor, CanClearFullscreen::kNo);
+                        this->clear(scissorRect, *constColor);
                         return QuadOptimization::kSubmitted;
                     }
                 }
@@ -956,7 +949,7 @@
         if (this->caps()->performStencilClearsAsDraws()) {
             // There is a driver bug with clearing stencil. We must use an op to manually clear the
             // stencil buffer before the op that required 'setNeedsStencil'.
-            this->internalStencilClear(GrFixedClip::Disabled(), /* inside mask */ false);
+            this->internalStencilClear(nullptr, /* inside mask */ false);
         } else {
             this->getOpsTask()->setInitialStencilContent(
                     GrOpsTask::StencilContent::kUserBitsCleared);
@@ -964,38 +957,30 @@
     }
 }
 
-void GrRenderTargetContextPriv::clearStencilClip(const GrFixedClip& clip, bool insideStencilMask) {
-    ASSERT_SINGLE_OWNER_PRIV
-    RETURN_IF_ABANDONED_PRIV
-    SkDEBUGCODE(fRenderTargetContext->validate();)
-    GR_CREATE_TRACE_MARKER_CONTEXT("GrRenderTargetContextPriv", "clearStencilClip",
-                                   fRenderTargetContext->fContext);
-
-    AutoCheckFlush acf(fRenderTargetContext->drawingManager());
-
-    fRenderTargetContext->internalStencilClear(clip, insideStencilMask);
-}
-
-void GrRenderTargetContext::internalStencilClear(const GrFixedClip& clip, bool insideStencilMask) {
+void GrRenderTargetContext::internalStencilClear(const SkIRect* scissor, bool insideStencilMask) {
     this->setNeedsStencil(/* useMixedSamplesIfNotMSAA = */ false);
 
     bool clearWithDraw = this->caps()->performStencilClearsAsDraws() ||
-                         (clip.scissorEnabled() && this->caps()->performPartialClearsAsDraws());
-    // TODO(michaelludwig): internalStencilClear will eventually just take a GrScissorState so
-    // we won't need to check window rectangles here.
-    if (clearWithDraw || clip.hasWindowRectangles()) {
+                         (scissor && this->caps()->performPartialClearsAsDraws());
+    if (clearWithDraw) {
         const GrUserStencilSettings* ss = GrStencilSettings::SetClipBitSettings(insideStencilMask);
-        SkRect rect = clip.scissorEnabled() ? SkRect::Make(clip.scissorRect())
-                                            : SkRect::MakeWH(this->width(), this->height());
+        SkRect rect = scissor ? SkRect::Make(*scissor)
+                              : SkRect::MakeWH(this->width(), this->height());
 
         // Configure the paint to have no impact on the color buffer
         GrPaint paint;
         paint.setXPFactory(GrDisableColorXPFactory::Get());
-        this->addDrawOp(clip, GrFillRectOp::MakeNonAARect(fContext, std::move(paint), SkMatrix::I(),
-                                                          rect, ss));
+        this->addDrawOp(GrFixedClip::Disabled(),
+                        GrFillRectOp::MakeNonAARect(fContext, std::move(paint), SkMatrix::I(),
+                                                    rect, ss));
     } else {
+        GrScissorState scissorState;
+        if (scissor) {
+            scissorState.set(*scissor);
+        }
+
         std::unique_ptr<GrOp> op(GrClearStencilClipOp::Make(
-                fContext, clip.scissorState(), insideStencilMask, this->asRenderTargetProxy()));
+                fContext, scissorState, insideStencilMask, this->asRenderTargetProxy()));
         if (!op) {
             return;
         }