Add an heuristic for promoting canvases to GPU acceleration

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

Index: third_party/WebKit/Source/platform/graphics/ImageBuffer.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/ImageBuffer.cpp b/third_party/WebKit/Source/platform/graphics/ImageBuffer.cpp
index 4982dd7ed2ec559b27a7c809271d21f025a70e0f..493a379ba87340d99138418c06cc12e8e5a1ae15 100644
--- a/third_party/WebKit/Source/platform/graphics/ImageBuffer.cpp
+++ b/third_party/WebKit/Source/platform/graphics/ImageBuffer.cpp
@@ -146,16 +146,6 @@ 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();
@@ -367,8 +357,9 @@ bool ImageBuffer::getImageData(Multiply multiplied,
   DCHECK(canvas());
 
   if (ExpensiveCanvasHeuristicParameters::GetImageDataForcesNoAcceleration &&
-      !RuntimeEnabledFeatures::canvas2dFixedRenderingModeEnabled())
+      !RuntimeEnabledFeatures::canvas2dFixedRenderingModeEnabled()) {
     const_cast<ImageBuffer*>(this)->disableAcceleration();
+  }
 
   sk_sp<SkImage> snapshot = m_surface->newImageSnapshot(
       PreferNoAcceleration, SnapshotReasonGetImageData);
@@ -442,22 +433,22 @@ void ImageBuffer::putByteArray(Multiply multiplied,
   if (!isSurfaceValid())
     return;
 
-  ASSERT(sourceRect.width() > 0);
-  ASSERT(sourceRect.height() > 0);
+  DCHECK_GT(sourceRect.width(), 0);
+  DCHECK_GT(sourceRect.height(), 0);
 
   int originX = sourceRect.x();
   int destX = destPoint.x() + sourceRect.x();
-  ASSERT(destX >= 0);
-  ASSERT(destX < m_surface->size().width());
-  ASSERT(originX >= 0);
-  ASSERT(originX < sourceRect.maxX());
+  DCHECK_GE(destX, 0);
+  DCHECK_LT(destX, m_surface->size().width());
+  DCHECK_GE(originX, 0);
+  DCHECK_LT(originX, sourceRect.maxX());
 
   int originY = sourceRect.y();
   int destY = destPoint.y() + sourceRect.y();
-  ASSERT(destY >= 0);
-  ASSERT(destY < m_surface->size().height());
-  ASSERT(originY >= 0);
-  ASSERT(originY < sourceRect.maxY());
+  DCHECK_GE(destY, 0);
+  DCHECK_LT(destY, m_surface->size().height());
+  DCHECK_GE(originY, 0);
+  DCHECK_LT(originY, sourceRect.maxY());
 
   const size_t srcBytesPerRow = 4 * sourceSize.width();
   const void* srcAddr = source + originY * srcBytesPerRow + originX * 4;
@@ -492,6 +483,9 @@ void ImageBuffer::updateGPUMemoryUsage() const {
     s_globalAcceleratedImageBufferCount--;
     s_globalGPUMemoryUsage -= m_gpuMemoryUsage;
     m_gpuMemoryUsage = 0;
+
+    if (m_client)
+      m_client->didDisableAcceleration();
   }
 }
 
@@ -519,12 +513,6 @@ void ImageBuffer::disableAcceleration() {
   if (!isAccelerated())
     return;
 
-  sk_sp<SkImage> image =
-      m_surface->newImageSnapshot(PreferNoAcceleration, SnapshotReasonPaint);
-  // Using a GPU-backed image with RecordingImageBufferSurface
-  // will fail at playback time.
-  image = image->makeNonTextureImage();
-
   // Create and configure a recording (unaccelerated) surface.
   std::unique_ptr<RecordingImageBufferFallbackSurfaceFactory> surfaceFactory =
       WTF::makeUnique<UnacceleratedSurfaceFactory>();
@@ -532,13 +520,26 @@ void ImageBuffer::disableAcceleration() {
       WTF::wrapUnique(new RecordingImageBufferSurface(
           m_surface->size(), std::move(surfaceFactory),
           m_surface->getOpacityMode(), m_surface->colorSpace()));
+  setSurface(std::move(surface));
+}
+
+void ImageBuffer::setSurface(std::unique_ptr<ImageBufferSurface> surface) {
+  sk_sp<SkImage> image =
+      m_surface->newImageSnapshot(PreferNoAcceleration, SnapshotReasonPaint);
+
+  if (surface->isRecording()) {
+    // Using a GPU-backed image with RecordingImageBufferSurface
+    // will fail at playback time.
+    image = image->makeNonTextureImage();
+  }
+
   surface->canvas()->drawImage(image.get(), 0, 0);
   surface->setImageBuffer(this);
   if (m_client)
     m_client->restoreCanvasMatrixClipStack(surface->canvas());
   m_surface = std::move(surface);
 
-  didDisableAcceleration();
+  updateGPUMemoryUsage();
 }
 
 bool ImageDataBuffer::encodeImage(const String& mimeType,
@@ -556,7 +557,7 @@ bool ImageDataBuffer::encodeImage(const String& mimeType,
   } else {
     if (!PNGImageEncoder::encode(*this, encodedImage))
       return false;
-    ASSERT(mimeType == "image/png");
+    DCHECK_EQ(mimeType, "image/png");
   }
 
   return true;
@@ -564,7 +565,7 @@ bool ImageDataBuffer::encodeImage(const String& mimeType,
 
 String ImageDataBuffer::toDataURL(const String& mimeType,
                                   const double& quality) const {
-  ASSERT(MIMETypeRegistry::isSupportedImageMIMETypeForEncoding(mimeType));
+  DCHECK(MIMETypeRegistry::isSupportedImageMIMETypeForEncoding(mimeType));
 
   Vector<unsigned char> result;
   if (!encodeImage(mimeType, quality, &result))