Improve usage of window rectangles

src/gpu/GrDrawContext.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrBatchTest.h"
 #include "GrColor.h"
 #include "GrDrawContext.h"
@@ skipping 196 matching lines @@
     SkDEBUGCODE(fDrawContext->validate();)
     GR_AUDIT_TRAIL_AUTO_FRAME(fDrawContext->fAuditTrail, "GrDrawContextPriv::clear");
 
     AutoCheckFlush acf(fDrawContext->fDrawingManager);
     fDrawContext->internalClear(clip, color, canIgnoreClip);
 }
 
 void GrDrawContext::internalClear(const GrFixedClip& clip,
                                   const GrColor color,
                                   bool canIgnoreClip) {
-    bool isFull = !clip.scissorEnabled() ||
-                  (canIgnoreClip && fContext->caps()->fullClearIsFree()) ||
-                  clip.scissorRect().contains(SkIRect::MakeWH(this->width(), this->height()));
+    bool isFull = false;
+    if (clip.windowRectsState().disabled()) {
+        isFull = !clip.scissorEnabled() ||
+                 (canIgnoreClip && fContext->caps()->fullClearIsFree()) ||
+                 clip.scissorRect().contains(SkIRect::MakeWH(this->width(), this->height()));
+    }
 
     if (fContext->caps()->useDrawInsteadOfClear()) {
         // This works around a driver bug with clear by drawing a rect instead.
         // The driver will ignore a clear if it is the only thing rendered to a
         // target before the target is read.
         SkRect clearRect = SkRect::MakeIWH(this->width(), this->height());
         if (isFull) {
             this->discard();
         } else if (!clearRect.intersect(SkRect::Make(clip.scissorRect()))) {
             return;
@@ skipping 1163 matching lines @@
 
 void GrDrawContext::drawBatch(const GrPipelineBuilder& pipelineBuilder, const GrClip& clip,
                               GrDrawBatch* batch) {
     ASSERT_SINGLE_OWNER
     RETURN_IF_ABANDONED
     SkDEBUGCODE(this->validate();)
     GR_AUDIT_TRAIL_AUTO_FRAME(fAuditTrail, "GrDrawContext::drawBatch");
 
     this->getDrawTarget()->drawBatch(pipelineBuilder, this, clip, batch);
 }