canvas: fix bugs on HTMLCanvasElement::copiedImage()

Source/core/html/canvas/WebGLRenderingContextBase.cpp

 /*
  * Copyright (C) 2009 Apple Inc. 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.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 876 matching lines @@
     if (!isContextLost())
         drawingBuffer()->setBufferClearNeeded(true);
 }
 
 void WebGLRenderingContextBase::setIsHidden(bool hidden)
 {
     if (drawingBuffer())
         drawingBuffer()->setIsHidden(hidden);
 }
 
-void WebGLRenderingContextBase::paintRenderingResultsToCanvas(SourceDrawingBuffer sourceBuffer)
+bool WebGLRenderingContextBase::paintRenderingResultsToCanvas(SourceDrawingBuffer sourceBuffer)
 {
     if (isContextLost())
-        return;
+        return false;
 
     bool mustClearNow = clearIfComposited() != Skipped;
     if (!m_markedCanvasDirty && !mustClearNow)
-        return;
+        return false;
 
     canvas()->clearCopiedImage();
     m_markedCanvasDirty = false;
 
     ScopedTexture2DRestorer restorer(this);
 
     drawingBuffer()->commit();
     if (!canvas()->buffer()->copyRenderingResultsFromDrawingBuffer(drawingBuffer(), sourceBuffer)) {
         canvas()->ensureUnacceleratedImageBuffer();
         if (canvas()->hasImageBuffer())
             drawingBuffer()->paintRenderingResultsToCanvas(canvas()->buffer());
     }
 
-    if (m_framebufferBinding)
-        webContext()->bindFramebuffer(GL_FRAMEBUFFER, objectOrZero(m_framebufferBinding.get()));
-    else
-        drawingBuffer()->bind();
+    restoreCurrentFramebuffer();
+    return true;
 }
 
 PassRefPtrWillBeRawPtr<ImageData> WebGLRenderingContextBase::paintRenderingResultsToImageData(SourceDrawingBuffer sourceBuffer)
 {
     if (isContextLost())
         return nullptr;
 
     clearIfComposited();
     drawingBuffer()->commit();
     int width, height;
@@ skipping 4931 matching lines @@
     return m_sharedWebGraphicsContext3D ? m_sharedWebGraphicsContext3D->drawingBuffer() : 0;
 }
 #else
 DrawingBuffer* WebGLRenderingContextBase::drawingBuffer() const
 {
     return m_drawingBuffer.get();
 }
 #endif
 
 } // namespace blink