Expose if we are using swiftshader via WebGraphicsContext3DProvider.

content/renderer/webgraphicscontext3d_provider_impl.cc

 // 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.
 
 #include "content/renderer/webgraphicscontext3d_provider_impl.h"
 
 #include "content/common/gpu/client/context_provider_command_buffer.h"
 #include "gpu/command_buffer/client/context_support.h"
 #include "third_party/WebKit/public/platform/functional/WebFunction.h"
 
 namespace content {
 
 WebGraphicsContext3DProviderImpl::WebGraphicsContext3DProviderImpl(
-    scoped_refptr<ContextProviderCommandBuffer> provider)
-    : provider_(std::move(provider)) {}
+    scoped_refptr<ContextProviderCommandBuffer> provider,
+    bool software_rendering)
+    : provider_(std::move(provider)), software_rendering_(software_rendering) {}
 
 WebGraphicsContext3DProviderImpl::~WebGraphicsContext3DProviderImpl() {}
 
 bool WebGraphicsContext3DProviderImpl::bindToCurrentThread() {
   return provider_->BindToCurrentThread();
 }
 
 gpu::gles2::GLES2Interface* WebGraphicsContext3DProviderImpl::contextGL() {
   return provider_->ContextGL();
 }
 
 GrContext* WebGraphicsContext3DProviderImpl::grContext() {
   return provider_->GrContext();
 }
 
 gpu::Capabilities WebGraphicsContext3DProviderImpl::getCapabilities() {
   return provider_->ContextCapabilities();
 }
 
+bool WebGraphicsContext3DProviderImpl::isSoftwareRendering() const {
+  return software_rendering_;
+}
+
 void WebGraphicsContext3DProviderImpl::setLostContextCallback(
     blink::WebClosure c) {
   provider_->SetLostContextCallback(c.TakeBaseCallback());
 }
 
 void WebGraphicsContext3DProviderImpl::setErrorMessageCallback(
     blink::WebFunction<void(const char*, int32_t)> c) {
   provider_->ContextSupport()->SetErrorMessageCallback(c.TakeBaseCallback());
 }
 
 }  // namespace content