Revert of Allow canvases to be GPU-accelerated in Workers

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

 /*
  * Copyright (c) 2013, Google Inc. 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
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 12 matching lines @@
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * 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/gpu/AcceleratedImageBufferSurface.h"
 
-#include "platform/graphics/gpu/SharedGpuContext.h"
 #include "platform/graphics/skia/SkiaUtils.h"
+#include "public/platform/Platform.h"
+#include "public/platform/WebGraphicsContext3DProvider.h"
 #include "skia/ext/texture_handle.h"
 #include "third_party/skia/include/gpu/GrContext.h"
 #include "wtf/PtrUtil.h"
 #include "wtf/RefPtr.h"
 
 namespace blink {
 
 AcceleratedImageBufferSurface::AcceleratedImageBufferSurface(const IntSize& size, OpacityMode opacityMode, sk_sp<SkColorSpace> colorSpace)
     : ImageBufferSurface(size, opacityMode, colorSpace)
 {
-    if (!SharedGpuContext::isValid())
+    m_contextProvider = wrapUnique(Platform::current()->createSharedOffscreenGraphicsContext3DProvider());
+    if (!m_contextProvider)
         return;
-    GrContext* grContext = SharedGpuContext::gr();
-    m_contextId = SharedGpuContext::contextId();
-    CHECK(grContext);
+    GrContext* grContext = m_contextProvider->grContext();
+    if (!grContext)
+        return;
 
     SkAlphaType alphaType = (Opaque == opacityMode) ? kOpaque_SkAlphaType : kPremul_SkAlphaType;
     SkImageInfo info = SkImageInfo::MakeN32(size.width(), size.height(), alphaType);
     SkSurfaceProps disableLCDProps(0, kUnknown_SkPixelGeometry);
     m_surface = SkSurface::MakeRenderTarget(grContext, SkBudgeted::kYes, info, 0 /* sampleCount */,
         Opaque == opacityMode ? nullptr : &disableLCDProps);
     if (!m_surface.get())
         return;
     clear();
 }
 
-bool AcceleratedImageBufferSurface::isValid() const
-{
-    return m_surface && SharedGpuContext::isValid() && m_contextId == SharedGpuContext::contextId();
-}
-
 sk_sp<SkImage> AcceleratedImageBufferSurface::newImageSnapshot(AccelerationHint, SnapshotReason)
 {
     return m_surface->makeImageSnapshot();
 }
 
 GLuint AcceleratedImageBufferSurface::getBackingTextureHandleForOverwrite()
 {
     if (!m_surface)
         return 0;
     return skia::GrBackendObjectToGrGLTextureInfo(m_surface->getTextureHandle(SkSurface::kDiscardWrite_TextureHandleAccess))->fID;
 }
 
 } // namespace blink