[DevTools] Move Page and Emulation handlers to RenderFrameHostImpl.

BUG=470453

Review URL: https://codereview.chromium.org/1043173003

Cr-Commit-Position: refs/heads/master@{#324228}

content/browser/devtools/protocol/color_picker.cc

@@ -33,7 +33,7 @@ ColorPicker::ColorPicker(ColorPickedCallback callback)
 ColorPicker::~ColorPicker() {
 }
 
-void ColorPicker::SetRenderViewHost(RenderViewHostImpl* host) {
+void ColorPicker::SetRenderWidgetHost(RenderWidgetHostImpl* host) {
   if (host_ == host)
     return;
 

content/browser/devtools/protocol/color_picker.h

@@ -15,7 +15,7 @@ class WebMouseEvent;
 
 namespace content {
 
-class RenderViewHostImpl;
+class RenderWidgetHostImpl;
 
 namespace devtools {
 namespace page {
@@ -27,7 +27,7 @@ class ColorPicker {
   explicit ColorPicker(ColorPickedCallback callback);
   virtual ~ColorPicker();
 
-  void SetRenderViewHost(RenderViewHostImpl* host);
+  void SetRenderWidgetHost(RenderWidgetHostImpl* host);
   void SetEnabled(bool enabled);
   void OnSwapCompositorFrame();
 
@@ -44,7 +44,7 @@ class ColorPicker {
   int last_cursor_x_;
   int last_cursor_y_;
   RenderWidgetHost::MouseEventCallback mouse_event_callback_;
-  RenderViewHostImpl* host_;
+  RenderWidgetHostImpl* host_;
   base::WeakPtrFactory<ColorPicker> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ColorPicker);

content/browser/devtools/protocol/emulation_handler.cc

@@ -5,8 +5,9 @@
 #include "content/browser/devtools/protocol/emulation_handler.h"
 
 #include "base/strings/string_number_conversions.h"
+#include "content/browser/frame_host/render_frame_host_impl.h"
 #include "content/browser/geolocation/geolocation_service_context.h"
-#include "content/browser/renderer_host/render_view_host_impl.h"
+#include "content/browser/renderer_host/render_widget_host_impl.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/common/view_messages.h"
 #include "content/public/common/url_constants.h"
@@ -52,7 +53,7 @@ void EmulationHandler::ScreencastEnabledChanged() {
    UpdateTouchEventEmulationState();
 }
 
-void EmulationHandler::SetRenderViewHost(RenderViewHostImpl* host) {
+void EmulationHandler::SetRenderFrameHost(RenderFrameHostImpl* host) {
   if (host_ == host)
     return;
 
@@ -70,16 +71,11 @@ void EmulationHandler::Detached() {
 
 Response EmulationHandler::SetGeolocationOverride(
     double* latitude, double* longitude, double* accuracy) {
-  if (!host_)
+  if (!GetWebContents())
     return Response::InternalError("Could not connect to view");
 
-  WebContentsImpl* web_contents = static_cast<WebContentsImpl*>(
-      WebContents::FromRenderViewHost(host_));
-  if (!web_contents)
-    return Response::InternalError("No WebContents to override");
-
   GeolocationServiceContext* geolocation_context =
-      web_contents->GetGeolocationServiceContext();
+      GetWebContents()->GetGeolocationServiceContext();
   scoped_ptr<Geoposition> geoposition(new Geoposition());
   if (latitude && longitude && accuracy) {
     geoposition->latitude = *latitude;
@@ -97,16 +93,11 @@ Response EmulationHandler::SetGeolocationOverride(
 }
 
 Response EmulationHandler::ClearGeolocationOverride() {
-  if (!host_)
+  if (!GetWebContents())
     return Response::InternalError("Could not connect to view");
 
-  WebContentsImpl* web_contents = static_cast<WebContentsImpl*>(
-      WebContents::FromRenderViewHost(host_));
-  if (!web_contents)
-    return Response::InternalError("No WebContents to override");
-
   GeolocationServiceContext* geolocation_context =
-      web_contents->GetGeolocationServiceContext();
+      GetWebContents()->GetGeolocationServiceContext();
   geolocation_context->ClearOverride();
   return Response::OK();
 }
@@ -124,18 +115,11 @@ Response EmulationHandler::CanEmulate(bool* result) {
 #if defined(OS_ANDROID)
   *result = false;
 #else
-  if (host_) {
-    if (WebContents* web_contents = WebContents::FromRenderViewHost(host_)) {
-      *result = web_contents->GetMainFrame()->GetRenderViewHost() == host_;
+  *result = true;
 #if defined(DEBUG_DEVTOOLS)
+  if (WebContentsImpl* web_contents = GetWebContents())
     *result &= !web_contents->GetVisibleURL().SchemeIs(kChromeDevToolsScheme);
 #endif  // defined(DEBUG_DEVTOOLS)
-    } else {
-      *result = true;
-    }
-  } else {
-    *result = true;
-  }
 #endif  // defined(OS_ANDROID)
   return Response::OK();
 }
@@ -194,28 +178,37 @@ Response EmulationHandler::ClearDeviceMetricsOverride() {
   return Response::OK();
 }
 
+WebContentsImpl* EmulationHandler::GetWebContents() {
+  return host_ ?
+      static_cast<WebContentsImpl*>(WebContents::FromRenderFrameHost(host_)) :
+      nullptr;
+}
+
 void EmulationHandler::UpdateTouchEventEmulationState() {
+  RenderWidgetHostImpl* widget_host =
+      host_ ? host_->GetRenderWidgetHost() : nullptr;
   if (!host_)
     return;
   bool enabled = touch_emulation_enabled_ ||
       page_handler_->screencast_enabled();
   ui::GestureProviderConfigType config_type =
       TouchEmulationConfigurationToType(touch_emulation_configuration_);
-  host_->SetTouchEventEmulationEnabled(enabled, config_type);
-  WebContentsImpl* web_contents = static_cast<WebContentsImpl*>(
-      WebContents::FromRenderViewHost(host_));
-  if (web_contents)
-    web_contents->SetForceDisableOverscrollContent(enabled);
+  widget_host->SetTouchEventEmulationEnabled(enabled, config_type);
+  if (GetWebContents())
+    GetWebContents()->SetForceDisableOverscrollContent(enabled);
 }
 
 void EmulationHandler::UpdateDeviceEmulationState() {
+  RenderWidgetHostImpl* widget_host =
+      host_ ? host_->GetRenderWidgetHost() : nullptr;
   if (!host_)
     return;
   if (device_emulation_enabled_) {
-    host_->Send(new ViewMsg_EnableDeviceEmulation(
-        host_->GetRoutingID(), device_emulation_params_));
+    widget_host->Send(new ViewMsg_EnableDeviceEmulation(
+        widget_host->GetRoutingID(), device_emulation_params_));
   } else {
-    host_->Send(new ViewMsg_DisableDeviceEmulation(host_->GetRoutingID()));
+    widget_host->Send(new ViewMsg_DisableDeviceEmulation(
+        widget_host->GetRoutingID()));
   }
 }
 

content/browser/devtools/protocol/emulation_handler.h

@@ -11,7 +11,8 @@
 
 namespace content {
 
-class RenderViewHostImpl;
+class RenderFrameHostImpl;
+class WebContentsImpl;
 
 namespace devtools {
 
@@ -29,7 +30,7 @@ class EmulationHandler : public page::PageHandler::ScreencastListener {
   // page::PageHandler::ScreencastListener implementation.
   void ScreencastEnabledChanged() override;
 
-  void SetRenderViewHost(RenderViewHostImpl* host);
+  void SetRenderFrameHost(RenderFrameHostImpl* host);
   void Detached();
 
   Response SetGeolocationOverride(double* latitude,
@@ -52,6 +53,7 @@ class EmulationHandler : public page::PageHandler::ScreencastListener {
   Response ClearDeviceMetricsOverride();
 
  private:
+  WebContentsImpl* GetWebContents();
   void UpdateTouchEventEmulationState();
   void UpdateDeviceEmulationState();
 
@@ -62,7 +64,7 @@ class EmulationHandler : public page::PageHandler::ScreencastListener {
   blink::WebDeviceEmulationParams device_emulation_params_;
 
   page::PageHandler* page_handler_;
-  RenderViewHostImpl* host_;
+  RenderFrameHostImpl* host_;
 
   DISALLOW_COPY_AND_ASSIGN(EmulationHandler);
 };

content/browser/devtools/protocol/page_handler.cc

@@ -12,7 +12,7 @@
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/worker_pool.h"
 #include "content/browser/devtools/protocol/color_picker.h"
-#include "content/browser/renderer_host/render_view_host_impl.h"
+#include "content/browser/renderer_host/render_widget_host_impl.h"
 #include "content/browser/renderer_host/render_widget_host_view_base.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/common/view_messages.h"
@@ -20,6 +20,8 @@
 #include "content/public/browser/javascript_dialog_manager.h"
 #include "content/public/browser/navigation_controller.h"
 #include "content/public/browser/navigation_entry.h"
+#include "content/public/browser/notification_service.h"
+#include "content/public/browser/notification_types.h"
 #include "content/public/browser/storage_partition.h"
 #include "content/public/browser/web_contents_delegate.h"
 #include "content/public/common/referrer.h"
@@ -106,12 +108,29 @@ PageHandler::PageHandler()
 PageHandler::~PageHandler() {
 }
 
-void PageHandler::SetRenderViewHost(RenderViewHostImpl* host) {
+void PageHandler::SetRenderFrameHost(RenderFrameHostImpl* host) {
   if (host_ == host)
     return;
 
-  color_picker_->SetRenderViewHost(host);
+  RenderWidgetHostImpl* widget_host =
+      host_ ? host_->GetRenderWidgetHost() : nullptr;
+  if (widget_host) {
+    registrar_.Remove(
+        this,
+        content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED,
+        content::Source<RenderWidgetHost>(widget_host));
+  }
+
   host_ = host;
+  widget_host = host_ ? host_->GetRenderWidgetHost() : nullptr;
+  color_picker_->SetRenderWidgetHost(widget_host);
+
+  if (widget_host) {
+    registrar_.Add(
+        this,
+        content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED,
+        content::Source<RenderWidgetHost>(widget_host));
+  }
 }
 
 void PageHandler::SetClient(scoped_ptr<Client> client) {
@@ -134,9 +153,13 @@ void PageHandler::OnSwapCompositorFrame(
   color_picker_->OnSwapCompositorFrame();
 }
 
-void PageHandler::OnVisibilityChanged(bool visible) {
+void PageHandler::Observe(int type,
+                          const NotificationSource& source,
+                          const NotificationDetails& details) {
   if (!screencast_enabled_)
     return;
+  DCHECK(type == content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED);
+  bool visible = *Details<bool>(details).ptr();
   NotifyScreencastVisibility(visible);
 }
 
@@ -173,12 +196,9 @@ Response PageHandler::Disable() {
 Response PageHandler::Reload(const bool* ignoreCache,
                              const std::string* script_to_evaluate_on_load,
                              const std::string* script_preprocessor) {
-  if (!host_)
-    return Response::InternalError("Could not connect to view");
-
-  WebContents* web_contents = WebContents::FromRenderViewHost(host_);
+  WebContentsImpl* web_contents = GetWebContents();
   if (!web_contents)
-    return Response::InternalError("No WebContents to reload");
+    return Response::InternalError("Could not connect to view");
 
   // Handle in browser only if it is crashed.
   if (!web_contents->IsCrashed())
@@ -194,12 +214,9 @@ Response PageHandler::Navigate(const std::string& url,
   if (!gurl.is_valid())
     return Response::InternalError("Cannot navigate to invalid URL");
 
-  if (!host_)
-    return Response::InternalError("Could not connect to view");
-
-  WebContents* web_contents = WebContents::FromRenderViewHost(host_);
+  WebContentsImpl* web_contents = GetWebContents();
   if (!web_contents)
-    return Response::InternalError("No WebContents to navigate");
+    return Response::InternalError("Could not connect to view");
 
   web_contents->GetController()
       .LoadURL(gurl, Referrer(), ui::PAGE_TRANSITION_TYPED, std::string());
@@ -208,12 +225,9 @@ Response PageHandler::Navigate(const std::string& url,
 
 Response PageHandler::GetNavigationHistory(int* current_index,
                                            NavigationEntries* entries) {
-  if (!host_)
-    return Response::InternalError("Could not connect to view");
-
-  WebContents* web_contents = WebContents::FromRenderViewHost(host_);
+  WebContentsImpl* web_contents = GetWebContents();
   if (!web_contents)
-    return Response::InternalError("No WebContents to navigate");
+    return Response::InternalError("Could not connect to view");
 
   NavigationController& controller = web_contents->GetController();
   *current_index = controller.GetCurrentEntryIndex();
@@ -228,12 +242,9 @@ Response PageHandler::GetNavigationHistory(int* current_index,
 }
 
 Response PageHandler::NavigateToHistoryEntry(int entry_id) {
-  if (!host_)
-    return Response::InternalError("Could not connect to view");
-
-  WebContents* web_contents = WebContents::FromRenderViewHost(host_);
+  WebContentsImpl* web_contents = GetWebContents();
   if (!web_contents)
-    return Response::InternalError("No WebContents to navigate");
+    return Response::InternalError("Could not connect to view");
 
   NavigationController& controller = web_contents->GetController();
   for (int i = 0; i != controller.GetEntryCount(); ++i) {
@@ -247,10 +258,10 @@ Response PageHandler::NavigateToHistoryEntry(int entry_id) {
 }
 
 Response PageHandler::CaptureScreenshot(DevToolsCommandId command_id) {
-  if (!host_ || !host_->GetView())
+  if (!host_ || !host_->GetRenderWidgetHost())
     return Response::InternalError("Could not connect to view");
 
-  host_->GetSnapshotFromBrowser(
+  host_->GetRenderWidgetHost()->GetSnapshotFromBrowser(
       base::Bind(&PageHandler::ScreenshotCaptured,
           weak_factory_.GetWeakPtr(), command_id));
   return Response::OK();
@@ -269,7 +280,9 @@ Response PageHandler::StartScreencast(const std::string* format,
                                       const int* quality,
                                       const int* max_width,
                                       const int* max_height) {
-  if (!host_)
+  RenderWidgetHostImpl* widget_host =
+      host_ ? host_->GetRenderWidgetHost() : nullptr;
+  if (!widget_host)
     return Response::InternalError("Could not connect to view");
 
   screencast_enabled_ = true;
@@ -280,13 +293,15 @@ Response PageHandler::StartScreencast(const std::string* format,
   screencast_max_width_ = max_width ? *max_width : -1;
   screencast_max_height_ = max_height ? *max_height : -1;
 
-  bool visible = !host_->is_hidden();
+  bool visible = !widget_host->is_hidden();
   NotifyScreencastVisibility(visible);
   if (visible) {
-    if (has_compositor_frame_metadata_)
+    if (has_compositor_frame_metadata_) {
       InnerSwapCompositorFrame();
-    else
-      host_->Send(new ViewMsg_ForceRedraw(host_->GetRoutingID(), 0));
+    } else {
+      widget_host->Send(
+          new ViewMsg_ForceRedraw(widget_host->GetRoutingID(), 0));
+    }
   }
   if (screencast_listener_)
     screencast_listener_->ScreencastEnabledChanged();
@@ -311,12 +326,9 @@ Response PageHandler::HandleJavaScriptDialog(bool accept,
   if (prompt_text)
     prompt_override = base::UTF8ToUTF16(*prompt_text);
 
-  if (!host_)
-    return Response::InternalError("Could not connect to view");
-
-  WebContents* web_contents = WebContents::FromRenderViewHost(host_);
+  WebContentsImpl* web_contents = GetWebContents();
   if (!web_contents)
-    return Response::InternalError("No JavaScript dialog to handle");
+    return Response::InternalError("Could not connect to view");
 
   JavaScriptDialogManager* manager =
       web_contents->GetDelegate()->GetJavaScriptDialogManager(web_contents);
@@ -341,6 +353,12 @@ Response PageHandler::SetColorPickerEnabled(bool enabled) {
   return Response::OK();
 }
 
+WebContentsImpl* PageHandler::GetWebContents() {
+  return host_ ?
+      static_cast<WebContentsImpl*>(WebContents::FromRenderFrameHost(host_)) :
+      nullptr;
+}
+
 void PageHandler::NotifyScreencastVisibility(bool visible) {
   if (visible)
     capture_retry_count_ = kCaptureRetryLimit;

content/browser/devtools/protocol/page_handler.h

@@ -11,20 +11,23 @@
 #include "base/time/time.h"
 #include "cc/output/compositor_frame_metadata.h"
 #include "content/browser/devtools/protocol/devtools_protocol_handler.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/readback_types.h"
 
 class SkBitmap;
 
 namespace content {
 
-class RenderViewHostImpl;
+class RenderFrameHostImpl;
+class WebContentsImpl;
 
 namespace devtools {
 namespace page {
 
 class ColorPicker;
 
-class PageHandler {
+class PageHandler : public NotificationObserver {
  public:
   typedef DevToolsProtocolClient::Response Response;
 
@@ -35,13 +38,12 @@ class PageHandler {
   };
 
   PageHandler();
-  virtual ~PageHandler();
+  ~PageHandler() override;
 
-  void SetRenderViewHost(RenderViewHostImpl* host);
+  void SetRenderFrameHost(RenderFrameHostImpl* host);
   void SetClient(scoped_ptr<Client> client);
   void Detached();
   void OnSwapCompositorFrame(const cc::CompositorFrameMetadata& frame_metadata);
-  void OnVisibilityChanged(bool visible);
   void DidAttachInterstitialPage();
   void DidDetachInterstitialPage();
   void SetScreencastListener(ScreencastListener* listener);
@@ -80,6 +82,7 @@ class PageHandler {
   Response SetColorPickerEnabled(bool enabled);
 
  private:
+  WebContentsImpl* GetWebContents();
   void NotifyScreencastVisibility(bool visible);
   void InnerSwapCompositorFrame();
   void ScreencastFrameCaptured(const cc::CompositorFrameMetadata& metadata,
@@ -96,6 +99,11 @@ class PageHandler {
 
   void OnColorPicked(int r, int g, int b, int a);
 
+  // NotificationObserver overrides.
+  void Observe(int type,
+               const NotificationSource& source,
+               const NotificationDetails& details) override;
+
   bool enabled_;
 
   bool screencast_enabled_;
@@ -113,9 +121,10 @@ class PageHandler {
 
   scoped_ptr<ColorPicker> color_picker_;
 
-  RenderViewHostImpl* host_;
+  RenderFrameHostImpl* host_;
   scoped_ptr<Client> client_;
   ScreencastListener* screencast_listener_;
+  NotificationRegistrar registrar_;
   base::WeakPtrFactory<PageHandler> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PageHandler);

content/browser/devtools/render_frame_devtools_agent_host.cc

@@ -28,8 +28,6 @@
 #include "content/common/view_messages.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/content_browser_client.h"
-#include "content/public/browser/notification_service.h"
-#include "content/public/browser/notification_types.h"
 #include "content/public/browser/render_widget_host_iterator.h"
 #include "content/public/browser/web_contents_delegate.h"
 
@@ -141,26 +139,32 @@ RenderFrameDevToolsAgentHost::RenderFrameDevToolsAgentHost(RenderFrameHost* rfh)
       input_handler_(new devtools::input::InputHandler()),
       inspector_handler_(new devtools::inspector::InspectorHandler()),
       network_handler_(new devtools::network::NetworkHandler()),
-      page_handler_(new devtools::page::PageHandler()),
+      page_handler_(nullptr),
       power_handler_(new devtools::power::PowerHandler()),
       service_worker_handler_(
           new devtools::service_worker::ServiceWorkerHandler()),
       tracing_handler_(new devtools::tracing::TracingHandler(
           devtools::tracing::TracingHandler::Renderer)),
-      emulation_handler_(new devtools::emulation::EmulationHandler(
-          page_handler_.get())),
+      emulation_handler_(nullptr),
       frame_trace_recorder_(new DevToolsFrameTraceRecorder()),
       reattaching_(false) {
   DevToolsProtocolDispatcher* dispatcher = protocol_handler_->dispatcher();
   dispatcher->SetDOMHandler(dom_handler_.get());
-  dispatcher->SetEmulationHandler(emulation_handler_.get());
   dispatcher->SetInputHandler(input_handler_.get());
   dispatcher->SetInspectorHandler(inspector_handler_.get());
   dispatcher->SetNetworkHandler(network_handler_.get());
-  dispatcher->SetPageHandler(page_handler_.get());
   dispatcher->SetPowerHandler(power_handler_.get());
   dispatcher->SetServiceWorkerHandler(service_worker_handler_.get());
   dispatcher->SetTracingHandler(tracing_handler_.get());
+
+  if (!rfh->GetParent()) {
+    page_handler_.reset(new devtools::page::PageHandler());
+    emulation_handler_.reset(
+        new devtools::emulation::EmulationHandler(page_handler_.get()));
+    dispatcher->SetPageHandler(page_handler_.get());
+    dispatcher->SetEmulationHandler(emulation_handler_.get());
+  }
+
   SetRenderFrameHost(rfh);
   g_instances.Get().push_back(this);
   AddRef();  // Balanced in RenderFrameHostDestroyed.
@@ -217,7 +221,9 @@ void RenderFrameDevToolsAgentHost::OnClientDetached() {
 #if defined(OS_ANDROID)
   power_save_blocker_.reset();
 #endif
+  if (emulation_handler_)
     emulation_handler_->Detached();
+  if (page_handler_)
     page_handler_->Detached();
   power_handler_->Detached();
   service_worker_handler_->Detached();
@@ -365,6 +371,7 @@ bool RenderFrameDevToolsAgentHost::OnMessageReceived(
 }
 
 void RenderFrameDevToolsAgentHost::DidAttachInterstitialPage() {
+  if (page_handler_)
     page_handler_->DidAttachInterstitialPage();
 
   if (!render_frame_host_)
@@ -380,6 +387,7 @@ void RenderFrameDevToolsAgentHost::DidAttachInterstitialPage() {
 }
 
 void RenderFrameDevToolsAgentHost::DidDetachInterstitialPage() {
+  if (page_handler_)
     page_handler_->DidDetachInterstitialPage();
 }
 
@@ -400,15 +408,6 @@ void RenderFrameDevToolsAgentHost::DidCommitProvisionalLoadForFrame(
   service_worker_handler_->UpdateHosts();
 }
 
-void RenderFrameDevToolsAgentHost::Observe(int type,
-                                          const NotificationSource& source,
-                                          const NotificationDetails& details) {
-  if (type == content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED) {
-    bool visible = *Details<bool>(details).ptr();
-    page_handler_->OnVisibilityChanged(visible);
-  }
-}
-
 void RenderFrameDevToolsAgentHost::SetRenderFrameHost(RenderFrameHost* rfh) {
   DCHECK(ShouldCreateDevToolsFor(rfh));
   DCHECK(!render_frame_host_);
@@ -418,32 +417,26 @@ void RenderFrameDevToolsAgentHost::SetRenderFrameHost(RenderFrameHost* rfh) {
   RenderViewHostImpl* rvh = static_cast<RenderViewHostImpl*>(
       rfh->GetRenderViewHost());
   dom_handler_->SetRenderFrameHost(render_frame_host_);
-  emulation_handler_->SetRenderViewHost(rvh);
   input_handler_->SetRenderViewHost(rvh);
   network_handler_->SetRenderFrameHost(render_frame_host_);
-  page_handler_->SetRenderViewHost(rvh);
   service_worker_handler_->SetRenderFrameHost(render_frame_host_);
 
-  registrar_.Add(
-      this,
-      content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED,
-      content::Source<RenderWidgetHost>(rvh));
+  if (emulation_handler_)
+    emulation_handler_->SetRenderFrameHost(render_frame_host_);
+  if (page_handler_)
+    page_handler_->SetRenderFrameHost(render_frame_host_);
 }
 
 void RenderFrameDevToolsAgentHost::ClearRenderFrameHost() {
   DCHECK(render_frame_host_);
-  RenderViewHostImpl* rvh = static_cast<RenderViewHostImpl*>(
-      render_frame_host_->GetRenderViewHost());
-  registrar_.Remove(
-      this,
-      content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED,
-      content::Source<RenderWidgetHost>(rvh));
   render_frame_host_ = nullptr;
   dom_handler_->SetRenderFrameHost(nullptr);
-  emulation_handler_->SetRenderViewHost(nullptr);
+  if (emulation_handler_)
+    emulation_handler_->SetRenderFrameHost(nullptr);
   input_handler_->SetRenderViewHost(nullptr);
   network_handler_->SetRenderFrameHost(nullptr);
-  page_handler_->SetRenderViewHost(nullptr);
+  if (page_handler_)
+    page_handler_->SetRenderFrameHost(nullptr);
   service_worker_handler_->SetRenderFrameHost(nullptr);
 }
 
@@ -512,6 +505,7 @@ void RenderFrameDevToolsAgentHost::OnSwapCompositorFrame(
   ViewHostMsg_SwapCompositorFrame::Param param;
   if (!ViewHostMsg_SwapCompositorFrame::Read(&message, &param))
     return;
+  if (page_handler_)
     page_handler_->OnSwapCompositorFrame(get<1>(param).metadata);
   frame_trace_recorder_->OnSwapCompositorFrame(
       render_frame_host_, get<1>(param).metadata);
@@ -521,6 +515,7 @@ void RenderFrameDevToolsAgentHost::SynchronousSwapCompositorFrame(
     const cc::CompositorFrameMetadata& frame_metadata) {
   if (!render_frame_host_)
     return;
+  if (page_handler_)
     page_handler_->OnSwapCompositorFrame(frame_metadata);
   frame_trace_recorder_->OnSwapCompositorFrame(
       render_frame_host_, frame_metadata);

content/browser/devtools/render_frame_devtools_agent_host.h

@@ -12,8 +12,6 @@
 #include "base/memory/scoped_ptr.h"
 #include "content/browser/devtools/ipc_devtools_agent_host.h"
 #include "content/common/content_export.h"
-#include "content/public/browser/notification_observer.h"
-#include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/web_contents_observer.h"
 
 namespace cc {
@@ -45,8 +43,7 @@ namespace tracing { class TracingHandler; }
 
 class CONTENT_EXPORT RenderFrameDevToolsAgentHost
     : public IPCDevToolsAgentHost,
-      private WebContentsObserver,
-      public NotificationObserver {
+      private WebContentsObserver {
  public:
   static void AddAllAgentHosts(DevToolsAgentHost::List* result);
 
@@ -104,11 +101,6 @@ class CONTENT_EXPORT RenderFrameDevToolsAgentHost
       const GURL& url,
       ui::PageTransition transition_type) override;
 
-  // NotificationObserver overrides:
-  void Observe(int type,
-               const NotificationSource& source,
-               const NotificationDetails& details) override;
-
   void DisconnectRenderFrameHost();
   void ConnectRenderFrameHost(RenderFrameHost* rvh);
   void ReattachToRenderFrameHost(RenderFrameHost* rvh);
@@ -145,7 +137,6 @@ class CONTENT_EXPORT RenderFrameDevToolsAgentHost
 #if defined(OS_ANDROID)
   scoped_ptr<PowerSaveBlockerImpl> power_save_blocker_;
 #endif
-  NotificationRegistrar registrar_;
   bool reattaching_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderFrameDevToolsAgentHost);