Attempt to throw away rrect clips of rrects.

src/core/SkClipStack.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkAtomics.h"
 #include "SkCanvas.h"
 #include "SkClipStack.h"
@@ skipping 628 matching lines @@
             }
         }
         if (SkRegion::kReplace_Op == element->getOp()) {
             break;
         }
         element = iter.prev();
     }
     return true;
 }
 
+bool SkClipStack::quickContains(const SkRRect& rrect) const {
+
+    Iter iter(*this, Iter::kTop_IterStart);
+    const Element* element = iter.prev();
+    while (element != nullptr) {
+        if (SkRegion::kIntersect_Op != element->getOp() && SkRegion::kReplace_Op != element->getOp())
+            return false;
+        if (element->isInverseFilled()) {
+            // Part of 'rrect' could be trimmed off by the inverse-filled clip element
+            if (SkRect::Intersects(element->getBounds(), rrect.getBounds())) {
+                return false;
+            }
+        } else {
+            if (!element->contains(rrect)) {
+                return false;
+            }
+        }
+        if (SkRegion::kReplace_Op == element->getOp()) {
+            break;
+        }
+        element = iter.prev();
+    }
+    return true;
+}
+
 bool SkClipStack::asPath(SkPath *path) const {
     bool isAA = false;
 
     path->reset();
     path->setFillType(SkPath::kInverseEvenOdd_FillType);
 
     SkClipStack::Iter iter(*this, SkClipStack::Iter::kBottom_IterStart);
     while (const SkClipStack::Element* element = iter.next()) {
         SkPath operand;
         if (element->getType() != SkClipStack::Element::kEmpty_Type) {
@@ skipping 252 matching lines @@
 
 void SkClipStack::dump() const {
     B2TIter iter(*this);
     const Element* e;
     while ((e = iter.next())) {
         e->dump();
         SkDebugf("\n");
     }
 }
 #endif