Allow canvases to be GPU-accelerated in Workers

third_party/WebKit/Source/platform/graphics/gpu/DrawingBuffer.cpp

Index: third_party/WebKit/Source/platform/graphics/gpu/DrawingBuffer.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/gpu/DrawingBuffer.cpp b/third_party/WebKit/Source/platform/graphics/gpu/DrawingBuffer.cpp
index b2c395f6d3d97a31fead115ea742925035837f99..d09b1226d10022808bd7f51bcee838befd18aee0 100644
--- a/third_party/WebKit/Source/platform/graphics/gpu/DrawingBuffer.cpp
+++ b/third_party/WebKit/Source/platform/graphics/gpu/DrawingBuffer.cpp
@@ -459,8 +459,6 @@ PassRefPtr<StaticBitmapImage> DrawingBuffer::transferToStaticBitmapImage()
     backendTexture.fTextureHandle = skia::GrGLTextureInfoToGrBackendObject(textureInfo);
     sk_sp<SkImage> skImage = SkImage::MakeFromAdoptedTexture(grContext, backendTexture);
 
-    // Hold a ref on the GrContext for the texture backing the |skImage|.
-    sk_sp<GrContext> grContextRef = sk_ref_sp(grContext);
     // We reuse the same mailbox name from above since our texture id was consumed from it.
     const auto& skImageMailbox = textureMailbox.mailbox();
     // Use the sync token generated after producing the mailbox. Waiting for this before trying to use
@@ -471,7 +469,7 @@ PassRefPtr<StaticBitmapImage> DrawingBuffer::transferToStaticBitmapImage()
 
     // TODO(xidachen): Create a small pool of recycled textures from ImageBitmapRenderingContext's
     // transferFromImageBitmap, and try to use them in DrawingBuffer.
-    return AcceleratedStaticBitmapImage::create(fromSkSp(skImage), grContextRef, skImageMailbox, skImageSyncToken);
+    return AcceleratedStaticBitmapImage::create(fromSkSp(skImage), grContext, skImageMailbox, skImageSyncToken);
 }
 
 DrawingBuffer::TextureParameters DrawingBuffer::chromiumImageTextureParameters()