Adding unit test for verifying copy on write in SkSurface + bug fix in SkCanvas::clear

src/core/SkCanvas.cpp

 
 /*
  * Copyright 2008 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "SkCanvas.h"
@@ skipping 1457 matching lines @@
     }
 }
 
 
 //////////////////////////////////////////////////////////////////////////////
 //  These are the virtual drawing methods
 //////////////////////////////////////////////////////////////////////////////
 
 void SkCanvas::clear(SkColor color) {
     SkDrawIter  iter(this);
-
+    this->predrawNotify();
     while (iter.next()) {
         iter.fDevice->clear(color);
     }
 }
 
 void SkCanvas::drawPaint(const SkPaint& paint) {
     this->internalDrawPaint(paint);
 }
 
 void SkCanvas::internalDrawPaint(const SkPaint& paint) {
@@ skipping 639 matching lines @@
     return *paint;
 }
 
 const SkRegion& SkCanvas::LayerIter::clip() const { return fImpl->getClip(); }
 int SkCanvas::LayerIter::x() const { return fImpl->getX(); }
 int SkCanvas::LayerIter::y() const { return fImpl->getY(); }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 SkCanvas::ClipVisitor::~ClipVisitor() { }