Expose if we are using swiftshader via WebGraphicsContext3DProvider.

content/renderer/webgraphicscontext3d_provider_impl.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_RENDERER_WEBGRAPHICSCONTEXT3D_PROVIDER_IMPL_H_
 #define CONTENT_RENDERER_WEBGRAPHICSCONTEXT3D_PROVIDER_IMPL_H_
 
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
 #include "content/common/content_export.h"
 #include "third_party/WebKit/public/platform/WebGraphicsContext3DProvider.h"
 
 namespace gpu {
 namespace gles2 {
 class GLES2Interface;
 }
 }
 
 namespace content {
 class ContextProviderCommandBuffer;
 
 class CONTENT_EXPORT WebGraphicsContext3DProviderImpl
     : public NON_EXPORTED_BASE(blink::WebGraphicsContext3DProvider) {
  public:
   explicit WebGraphicsContext3DProviderImpl(
-      scoped_refptr<ContextProviderCommandBuffer> provider);
+      scoped_refptr<ContextProviderCommandBuffer> provider,
+      bool software_rendering);
   ~WebGraphicsContext3DProviderImpl() override;
 
   // WebGraphicsContext3DProvider implementation.
   bool bindToCurrentThread() override;
   gpu::gles2::GLES2Interface* contextGL() override;
   GrContext* grContext() override;
   gpu::Capabilities getCapabilities() override;
+  bool isSoftwareRendering() const override;
   void setLostContextCallback(blink::WebClosure) override;
   void setErrorMessageCallback(
       blink::WebFunction<void(const char*, int32_t)>) override;
 
   ContextProviderCommandBuffer* context_provider() const {
     return provider_.get();
   }
 
  private:
   scoped_refptr<ContextProviderCommandBuffer> provider_;
+  const bool software_rendering_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_WEBGRAPHICSCONTEXT3D_PROVIDER_IMPL_H_