[devtools] Add a command to emulate the default background color.

third_party/WebKit/Source/web/InspectorEmulationAgent.h

 // Copyright 2015 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 InspectorEmulationAgent_h
 #define InspectorEmulationAgent_h
 
 #include "core/inspector/InspectorBaseAgent.h"
 #include "core/inspector/protocol/Emulation.h"
 #include "platform/WebTaskRunner.h"
 
 namespace blink {
 
 class WebLocalFrameImpl;
 class WebViewImpl;
 
+namespace protocol {
+namespace DOM {
+class RGBA;
+}  // namespace DOM
+}  // namespace protocol
+
 class InspectorEmulationAgent final
     : public InspectorBaseAgent<protocol::Emulation::Metainfo> {
   WTF_MAKE_NONCOPYABLE(InspectorEmulationAgent);
 
  public:
   class Client {
    public:
     virtual ~Client() {}
 
     virtual void setCPUThrottlingRate(double rate) {}
   };
 
   static InspectorEmulationAgent* create(WebLocalFrameImpl*, Client*);
   ~InspectorEmulationAgent() override;
 
   // protocol::Dispatcher::EmulationCommandHandler implementation.
   Response forceViewport(double x, double y, double scale) override;
   Response resetViewport() override;
   Response resetPageScaleFactor() override;
   Response setPageScaleFactor(double) override;
   Response setScriptExecutionDisabled(bool value) override;
   Response setTouchEmulationEnabled(bool enabled,
                                     Maybe<String> configuration) override;
   Response setEmulatedMedia(const String&) override;
   Response setCPUThrottlingRate(double) override;
   Response setVirtualTimePolicy(const String& policy,
                                 Maybe<int> virtualTimeBudgetMs) override;
+  Response setDefaultBackgroundColorOverride(
+      Maybe<protocol::DOM::RGBA>) override;
 
   // InspectorBaseAgent overrides.
   Response disable() override;
   void restore() override;
 
   DECLARE_VIRTUAL_TRACE();
 
  private:
   InspectorEmulationAgent(WebLocalFrameImpl*, Client*);
   WebViewImpl* webViewImpl();
   void virtualTimeBudgetExpired();
 
   Member<WebLocalFrameImpl> m_webLocalFrameImpl;
   Client* m_client;
   TaskHandle m_virtualTimeBudgetExpiredTaskHandle;
 };
 
 }  // namespace blink
 
 #endif  // !defined(InspectorEmulationAgent_h)