Move overdraw tracking code from GraphicsContext to CanvasRenderingContext2D

Source/core/html/HTMLCanvasElement.cpp

 /*
  * Copyright (C) 2004, 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 573 matching lines @@
             return adoptPtr(new UnacceleratedImageBufferSurface(deviceSize, opacityMode));
         return adoptPtr(new WebGLImageBufferSurface(deviceSize, opacityMode));
     }
 
     OwnPtr<RecordingImageBufferFallbackSurfaceFactory> surfaceFactory = createSurfaceFactory(deviceSize, msaaSampleCount);
 
     if (shouldUseDisplayList(deviceSize)) {
         OwnPtr<ImageBufferSurface> surface = adoptPtr(new RecordingImageBufferSurface(deviceSize, surfaceFactory.release(), opacityMode));
         if (surface->isValid())
             return surface.release();
-        surfaceFactory = createSurfaceFactory(deviceSize, msaaSampleCount); // recreate because old previous one was released
+        surfaceFactory = createSurfaceFactory(deviceSize, msaaSampleCount); // recreate because previous one was released
     }
 
     return surfaceFactory->createSurface(deviceSize, opacityMode);
 }
 
 void HTMLCanvasElement::createImageBuffer()
 {
-    createImageBufferInternal();
+    createImageBufferInternal(nullptr);
     if (m_didFailToCreateImageBuffer && m_context->is2d())
         toCanvasRenderingContext2D(m_context.get())->loseContext();
 }
 
-void HTMLCanvasElement::createImageBufferInternal()
+void HTMLCanvasElement::createImageBufferInternal(PassOwnPtr<ImageBufferSurface> externalSurface)
 {
     ASSERT(!m_imageBuffer);
     ASSERT(!m_contextStateSaver);
 
     m_didFailToCreateImageBuffer = true;
     m_imageBufferIsClear = true;
 
     if (!canCreateImageBuffer(size()))
         return;
 
-    int msaaSampleCount;
-    OwnPtr<ImageBufferSurface> surface = createImageBufferSurface(size(), &msaaSampleCount);
+    int msaaSampleCount = 0;
+    OwnPtr<ImageBufferSurface> surface;
+    if (externalSurface) {
+        surface = externalSurface;
+    } else {
+        surface = createImageBufferSurface(size(), &msaaSampleCount);
+    }
     m_imageBuffer = ImageBuffer::create(surface.release());
     if (!m_imageBuffer)
         return;
     m_imageBuffer->setClient(this);
 
     document().updateRenderTreeIfNeeded();
     RenderStyle* style = computedStyle();
     m_imageBuffer->setFilterLevel((style && (style->imageRendering() == ImageRenderingPixelated)) ? SkPaint::kNone_FilterLevel : SkPaint::kLow_FilterLevel);
 
     m_didFailToCreateImageBuffer = false;
@@ skipping 95 matching lines @@
 }
 
 ImageBuffer* HTMLCanvasElement::buffer() const
 {
     ASSERT(m_context);
     if (!hasImageBuffer() && !m_didFailToCreateImageBuffer)
         const_cast<HTMLCanvasElement*>(this)->createImageBuffer();
     return m_imageBuffer.get();
 }
 
+void HTMLCanvasElement::createImageBufferUsingSurface(PassOwnPtr<ImageBufferSurface> surface)
+{
+    discardImageBuffer();
+    createImageBufferInternal(surface);
+}
+
 void HTMLCanvasElement::ensureUnacceleratedImageBuffer()
 {
     ASSERT(m_context);
     if ((hasImageBuffer() && !m_imageBuffer->isAccelerated()) || m_didFailToCreateImageBuffer)
         return;
     discardImageBuffer();
     OpacityMode opacityMode = m_context->hasAlpha() ? NonOpaque : Opaque;
     m_imageBuffer = ImageBuffer::create(size(), opacityMode);
     m_didFailToCreateImageBuffer = !m_imageBuffer;
 }
@@ skipping 103 matching lines @@
 bool HTMLCanvasElement::wouldTaintOrigin(SecurityOrigin*) const
 {
     return !originClean();
 }
 
 FloatSize HTMLCanvasElement::sourceSize() const
 {
     return FloatSize(width(), height());
 }
 
+bool HTMLCanvasElement::isOpaque() const
+{
+    return m_context && !m_context->hasAlpha();
 }
+
+} // blink