Treat calls to CanvasRenderingContext2D.clearRect as operations that clear the canvas

Source/platform/graphics/RecordingImageBufferSurface.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 
 #include "platform/graphics/RecordingImageBufferSurface.h"
 
 #include "platform/graphics/GraphicsContext.h"
 #include "platform/graphics/ImageBuffer.h"
@@ skipping 18 matching lines @@
 { }
 
 void RecordingImageBufferSurface::initializeCurrentFrame()
 {
     static SkRTreeFactory rTreeFactory;
     m_currentFrame = adoptPtr(new SkPictureRecorder);
     m_currentFrame->beginRecording(size().width(), size().height(), &rTreeFactory);
     m_initialSaveCount = m_currentFrame->getRecordingCanvas()->getSaveCount();
     if (m_graphicsContext) {
         m_graphicsContext->resetCanvas(m_currentFrame->getRecordingCanvas());
-        m_graphicsContext->setTrackOpaqueRegion(true);
+        m_graphicsContext->setRegionTrackingMode(GraphicsContext::RegionTrackingOverwrite);
     }
 }
 
 void RecordingImageBufferSurface::setImageBuffer(ImageBuffer* imageBuffer)
 {
     m_graphicsContext = imageBuffer ? imageBuffer->context() : 0;
     if (m_currentFrame && m_graphicsContext) {
-        m_graphicsContext->setTrackOpaqueRegion(true);
+        m_graphicsContext->setRegionTrackingMode(GraphicsContext::RegionTrackingOverwrite);
         m_graphicsContext->resetCanvas(m_currentFrame->getRecordingCanvas());
     }
 }
 
 void RecordingImageBufferSurface::willReadback()
 {
     fallBackToRasterCanvas();
 }
 
 void RecordingImageBufferSurface::fallBackToRasterCanvas()
 {
     if (m_rasterCanvas) {
         ASSERT(!m_currentFrame);
         return;
     }
 
     m_rasterCanvas = adoptPtr(SkCanvas::NewRasterN32(size().width(), size().height()));
 
     if (m_previousFrame) {
         m_previousFrame->draw(m_rasterCanvas.get());
         m_previousFrame.clear();
     }
     if (m_currentFrame) {
         RefPtr<SkPicture> currentPicture = adoptRef(m_currentFrame->endRecording());
         currentPicture->draw(m_rasterCanvas.get());
         m_currentFrame.clear();
     }
 
     if (m_graphicsContext) {
-        m_graphicsContext->setTrackOpaqueRegion(false);
+        m_graphicsContext->setRegionTrackingMode(GraphicsContext::RegionTrackingDisabled);
         m_graphicsContext->resetCanvas(m_rasterCanvas.get());
     }
 }
 
 SkCanvas* RecordingImageBufferSurface::canvas() const
 {
     if (m_rasterCanvas)
         return m_rasterCanvas.get();
 
     ASSERT(m_currentFrame->getRecordingCanvas());
@@ skipping 50 matching lines @@
 
     SkCanvas* newCanvas = m_currentFrame->getRecordingCanvas();
     newCanvas->concat(ctm);
     newCanvas->clipRect(clip);
 
     m_frameWasCleared = false;
     return true;
 }
 
 } // namespace WebCore