Allow creation of ImageBitmaps from WebGL canvases.

Source/core/page/ImageBitmap.cpp

Index: Source/core/page/ImageBitmap.cpp
diff --git a/Source/core/page/ImageBitmap.cpp b/Source/core/page/ImageBitmap.cpp
index 006594a9c0d14006d89babea9ddcc0687fc7b754..13f8debcfba3c0cd8a29e04838a7e5cdc44dc855 100644
--- a/Source/core/page/ImageBitmap.cpp
+++ b/Source/core/page/ImageBitmap.cpp
@@ -9,6 +9,7 @@
 #include "core/html/HTMLImageElement.h"
 #include "core/html/HTMLVideoElement.h"
 #include "core/html/ImageData.h"
+#include "core/html/canvas/CanvasRenderingContext.h"
 #include "core/platform/graphics/BitmapImage.h"
 #include "core/platform/graphics/GraphicsContext.h"
 #include "wtf/RefPtr.h"
@@ -78,6 +79,10 @@ ImageBitmap::ImageBitmap(HTMLCanvasElement* canvas, const IntRect& cropRect)
     IntRect srcRect = intersection(cropRect, IntRect(IntPoint(), canvasSize));
     IntRect dstRect(IntPoint(), srcRect.size());
 
+    CanvasRenderingContext* sourceContext = canvas->renderingContext();
+    if (sourceContext && sourceContext->is3d())
+        sourceContext->paintRenderingResultsToCanvas();
+
     m_buffer = ImageBuffer::create(canvasSize);
     m_buffer->context()->drawImageBuffer(canvas->buffer(), dstRect, srcRect);
     m_bitmap = m_buffer->copyImage(DontCopyBackingStore);