Expose if we are using swiftshader via WebGraphicsContext3DProvider.

third_party/WebKit/Source/platform/graphics/Canvas2DLayerBridge.cpp

 /*
  * Copyright (C) 2012 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:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 72 matching lines @@
     if (surface) {
         if (opacityMode == Opaque) {
             surface->getCanvas()->clear(SK_ColorBLACK);
         } else {
             surface->getCanvas()->clear(SK_ColorTRANSPARENT);
         }
     }
     return fromSkSp(surface);
 }
 
-PassRefPtr<Canvas2DLayerBridge> Canvas2DLayerBridge::create(const IntSize& size, int msaaSampleCount, OpacityMode opacityMode, AccelerationMode accelerationMode)
-{
-    TRACE_EVENT_INSTANT0("test_gpu", "Canvas2DLayerBridgeCreation", TRACE_EVENT_SCOPE_GLOBAL);
-    std::unique_ptr<WebGraphicsContext3DProvider> contextProvider = wrapUnique(Platform::current()->createSharedOffscreenGraphicsContext3DProvider());
-    if (!contextProvider)
-        return nullptr;
-    RefPtr<Canvas2DLayerBridge> layerBridge;
-    layerBridge = adoptRef(new Canvas2DLayerBridge(std::move(contextProvider), size, msaaSampleCount, opacityMode, accelerationMode));
-    return layerBridge.release();
-}
-
 Canvas2DLayerBridge::Canvas2DLayerBridge(std::unique_ptr<WebGraphicsContext3DProvider> contextProvider, const IntSize& size, int msaaSampleCount, OpacityMode opacityMode, AccelerationMode accelerationMode)
     : m_contextProvider(std::move(contextProvider))
     , m_logger(wrapUnique(new Logger))
     , m_weakPtrFactory(this)
     , m_imageBuffer(0)
     , m_msaaSampleCount(msaaSampleCount)
     , m_bytesAllocated(0)
     , m_haveRecordedDrawCommands(false)
     , m_destructionInProgress(false)
     , m_filterQuality(kLow_SkFilterQuality)
@@ skipping 888 matching lines @@
 Canvas2DLayerBridge::MailboxInfo::MailboxInfo() = default;
 Canvas2DLayerBridge::MailboxInfo::MailboxInfo(const MailboxInfo& other) = default;
 
 void Canvas2DLayerBridge::Logger::reportHibernationEvent(HibernationEvent event)
 {
     DEFINE_STATIC_LOCAL(EnumerationHistogram, hibernationHistogram, ("Canvas.HibernationEvents", HibernationEventCount));
     hibernationHistogram.count(event);
 }
 
 } // namespace blink