Allow RecordingImageBufferSurface to prevent fallback.

third_party/WebKit/Source/platform/graphics/RecordingImageBufferSurface.h

Index: third_party/WebKit/Source/platform/graphics/RecordingImageBufferSurface.h
diff --git a/third_party/WebKit/Source/platform/graphics/RecordingImageBufferSurface.h b/third_party/WebKit/Source/platform/graphics/RecordingImageBufferSurface.h
index 8ed5756c8c4a8ee02656fef359b197005f56dd2a..19938f7950befaa19fa57800ef348098e88f74cf 100644
--- a/third_party/WebKit/Source/platform/graphics/RecordingImageBufferSurface.h
+++ b/third_party/WebKit/Source/platform/graphics/RecordingImageBufferSurface.h
@@ -23,14 +23,16 @@ class PLATFORM_EXPORT RecordingImageBufferSurface : public ImageBufferSurface {
   USING_FAST_MALLOC(RecordingImageBufferSurface);
 
  public:
-  // If the fallbackFactory is null the buffer surface should only be used
-  // for one frame and should not be used for any operations which need a
-  // raster surface, (i.e. writePixels).
-  // Only #getRecord should be used to access the resulting frame.
-  RecordingImageBufferSurface(
-      const IntSize&,
-      OpacityMode = kNonOpaque,
-      const CanvasColorParams& = CanvasColorParams());
+  enum AllowFallback : bool { kDisallowFallback, kAllowFallback };
+
+  // If |AllowFallback| is kDisallowFallback the buffer surface should only be
+  // used for one frame and should not be used for any operations which need a
+  // raster surface, (i.e. WritePixels()).
+  // Only GetRecord() should be used to access the resulting frame.
+  RecordingImageBufferSurface(const IntSize&,
+                              AllowFallback,
+                              OpacityMode = kNonOpaque,
+                              const CanvasColorParams& = CanvasColorParams());
   ~RecordingImageBufferSurface() override;
 
   // Implementation of ImageBufferSurface interfaces
@@ -106,6 +108,7 @@ class PLATFORM_EXPORT RecordingImageBufferSurface : public ImageBufferSurface {
   bool FinalizeFrameInternal(FallbackReason*);
   int ApproximateOpCount();
 
+  const AllowFallback allow_fallback_;
   std::unique_ptr<PaintRecorder> current_frame_;
   sk_sp<PaintRecord> previous_frame_;
   std::unique_ptr<UnacceleratedImageBufferSurface> fallback_surface_;