canvas: make a temporary buffer when a context doesn't exist.

Source/core/frame/ImageBitmap.cpp

Index: Source/core/frame/ImageBitmap.cpp
diff --git a/Source/core/frame/ImageBitmap.cpp b/Source/core/frame/ImageBitmap.cpp
index 50290cbbeced454f1e425d3d0bf3966b3e73ba75..789b861c9e2a1b8f1bec8e32ba72f057ff50bfb0 100644
--- a/Source/core/frame/ImageBitmap.cpp
+++ b/Source/core/frame/ImageBitmap.cpp
@@ -5,10 +5,8 @@
 #include "config.h"
 #include "core/frame/ImageBitmap.h"
 
-#include "core/html/HTMLCanvasElement.h"
 #include "core/html/HTMLVideoElement.h"
 #include "core/html/ImageData.h"
-#include "core/html/canvas/CanvasRenderingContext.h"
 #include "platform/graphics/BitmapImage.h"
 #include "platform/graphics/GraphicsContext.h"
 #include "platform/graphics/ImageBuffer.h"
@@ -75,20 +73,6 @@ ImageBitmap::ImageBitmap(HTMLVideoElement* video, const IntRect& cropRect)
     m_bitmapRect = IntRect(IntPoint(std::max(0, -cropRect.x()), std::max(0, -cropRect.y())), srcRect.size());
 }
 
-ImageBitmap::ImageBitmap(HTMLCanvasElement* canvas, const IntRect& cropRect)
-    : m_imageElement(nullptr)
-    , m_cropRect(cropRect)
-    , m_bitmapOffset(IntPoint())
-{
-    CanvasRenderingContext* sourceContext = canvas->renderingContext();
-    if (sourceContext && sourceContext->is3d())
-        sourceContext->paintRenderingResultsToCanvas(BackBuffer);
-
-    IntRect srcRect = intersection(cropRect, IntRect(IntPoint(), canvas->size()));
-    m_bitmapRect = IntRect(IntPoint(std::max(0, -cropRect.x()), std::max(0, -cropRect.y())), srcRect.size());
-    m_bitmap = cropImage(canvas->buffer()->copyImage(CopyBackingStore).get(), cropRect);
-}
-
 ImageBitmap::ImageBitmap(ImageData* data, const IntRect& cropRect)
     : m_imageElement(nullptr)
     , m_cropRect(cropRect)
@@ -154,12 +138,6 @@ PassRefPtrWillBeRawPtr<ImageBitmap> ImageBitmap::create(HTMLVideoElement* video,
     return adoptRefWillBeNoop(new ImageBitmap(video, normalizedCropRect));
 }
 
-PassRefPtrWillBeRawPtr<ImageBitmap> ImageBitmap::create(HTMLCanvasElement* canvas, const IntRect& cropRect)
-{
-    IntRect normalizedCropRect = normalizeRect(cropRect);
-    return adoptRefWillBeNoop(new ImageBitmap(canvas, normalizedCropRect));
-}
-
 PassRefPtrWillBeRawPtr<ImageBitmap> ImageBitmap::create(ImageData* data, const IntRect& cropRect)
 {
     IntRect normalizedCropRect = normalizeRect(cropRect);