Make 2D canvas disable gpu acceleration when getImageData is called

third_party/WebKit/Source/platform/graphics/ImageBuffer.cpp

 /*
  * Copyright (c) 2008, Google Inc. All rights reserved.
  * Copyright (C) 2009 Dirk Schulze <krit@webkit.org>
  * 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:
  *
  *     * Redistributions of source code must retain the above copyright
@@ skipping 17 matching lines @@
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "platform/graphics/ImageBuffer.h"
 
 #include "gpu/command_buffer/client/gles2_interface.h"
 #include "platform/MIMETypeRegistry.h"
 #include "platform/geometry/IntRect.h"
+#include "platform/graphics/ExpensiveCanvasHeuristicParameters.h"
 #include "platform/graphics/GraphicsContext.h"
 #include "platform/graphics/ImageBufferClient.h"
 #include "platform/graphics/StaticBitmapImage.h"
 #include "platform/graphics/UnacceleratedImageBufferSurface.h"
 #include "platform/graphics/gpu/DrawingBuffer.h"
 #include "platform/graphics/gpu/Extensions3DUtil.h"
 #include "platform/graphics/skia/SkiaUtils.h"
 #include "platform/image-encoders/JPEGImageEncoder.h"
 #include "platform/image-encoders/PNGImageEncoder.h"
 #include "platform/image-encoders/WEBPImageEncoder.h"
@@ skipping 70 matching lines @@
 bool ImageBuffer::isSurfaceValid() const
 {
     return m_surface->isValid();
 }
 
 bool ImageBuffer::isDirty()
 {
     return m_client ? m_client->isDirty() : false;
 }
 
+void ImageBuffer::didDisableAcceleration() const
+{
+    DCHECK(m_gpuMemoryUsage);
+    DCHECK_GT(s_globalAcceleratedImageBufferCount, 0u);
+    if (m_client)
+        m_client->didDisableAcceleration();
+    s_globalAcceleratedImageBufferCount--;
+    s_globalGPUMemoryUsage -= m_gpuMemoryUsage;
+    m_gpuMemoryUsage = 0;
+}
+
 void ImageBuffer::didFinalizeFrame()
 {
     if (m_client)
         m_client->didFinalizeFrame();
 }
 
 void ImageBuffer::finalizeFrame(const FloatRect &dirtyRect)
 {
     m_surface->finalizeFrame(dirtyRect);
     didFinalizeFrame();
@@ skipping 162 matching lines @@
         void* data;
         WTF::ArrayBufferContents::allocateMemoryOrNull(allocSizeInBytes, WTF::ArrayBufferContents::ZeroInitialize, data);
         if (!data)
             return false;
         WTF::ArrayBufferContents result(data, allocSizeInBytes, WTF::ArrayBufferContents::NotShared);
         result.transfer(contents);
         return true;
     }
 
     DCHECK(canvas());
-    RefPtr<SkImage> snapshot = m_surface->newImageSnapshot(PreferNoAcceleration, SnapshotReasonGetImageData);
+    AccelerationHint hint = (ExpensiveCanvasHeuristicParameters::GetImageDataForcesNoAcceleration) ? ForceNoAcceleration : PreferNoAcceleration;
+    RefPtr<SkImage> snapshot = m_surface->newImageSnapshot(hint, SnapshotReasonGetImageData);
     if (!snapshot)
         return false;
 
     const bool mayHaveStrayArea =
         m_surface->isAccelerated() // GPU readback may fail silently
         || rect.x() < 0
         || rect.y() < 0
         || rect.maxX() > m_surface->size().width()
         || rect.maxY() > m_surface->size().height();
     size_t allocSizeInBytes = rect.width() * rect.height() * 4;
@@ skipping 91 matching lines @@
     ASSERT(MIMETypeRegistry::isSupportedImageMIMETypeForEncoding(mimeType));
 
     Vector<unsigned char> result;
     if (!encodeImage(mimeType, quality, &result))
         return "data:,";
 
     return "data:" + mimeType + ";base64," + base64Encode(result);
 }
 
 } // namespace blink