Implement lifetime observer on RenderWidgetHostViewBase.

content/browser/frame_host/render_widget_host_view_child_frame.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/browser/frame_host/render_widget_host_view_child_frame.h"
 
 #include <algorithm>
 #include <utility>
 #include <vector>
 
@@ skipping 185 matching lines @@
 
 void RenderWidgetHostViewChildFrame::RenderProcessGone(
     base::TerminationStatus status,
     int error_code) {
   if (frame_connector_)
     frame_connector_->RenderProcessGone();
   Destroy();
 }
 
 void RenderWidgetHostViewChildFrame::Destroy() {
+  // SurfaceIdNames registered with RenderWidgetHostInputEventRouter

[kenrb, 2016/02/22 17:05:10]

nit: s/SurfaceIdNames/SurfaceIdNamespaces

[wjmaclean, 2016/02/23 13:13:26]

Done.

+  // have already been cleared when RenderWidgetHostViewBase notified its
+  // observers of our impending destruction.
   if (frame_connector_) {
     frame_connector_->set_view(NULL);
     frame_connector_ = NULL;
   }
 
-  if (host_->delegate() && host_->delegate()->GetInputEventRouter()) {
-    host_->delegate()->GetInputEventRouter()->RemoveSurfaceIdNamespaceOwner(
-        GetSurfaceIdNamespace());
-  }
+  // We notify our observers about shutdown here since we are about to release
+  // host_ and do not want any event calls coming from
+  // RenderWidgetHostInputEventRouter afterwards.
+  NotifyObserversAboutShutdown();
 
   host_->SetView(NULL);
   host_ = NULL;
   base::MessageLoop::current()->DeleteSoon(FROM_HERE, this);
 }
 
 void RenderWidgetHostViewChildFrame::SetTooltipText(
     const base::string16& tooltip_text) {
 }
 
@@ skipping 131 matching lines @@
 
 void RenderWidgetHostViewChildFrame::UnlockMouse() {
 }
 
 uint32_t RenderWidgetHostViewChildFrame::GetSurfaceIdNamespace() {
   return id_allocator_->id_namespace();
 }
 
 void RenderWidgetHostViewChildFrame::ProcessKeyboardEvent(
     const NativeWebKeyboardEvent& event) {
-  if (!host_)
-    return;
-
   host_->ForwardKeyboardEvent(event);
 }
 
 void RenderWidgetHostViewChildFrame::ProcessMouseEvent(
     const blink::WebMouseEvent& event) {
-  if (!host_)
-    return;
-
   host_->ForwardMouseEvent(event);
 }
 
 void RenderWidgetHostViewChildFrame::ProcessMouseWheelEvent(
     const blink::WebMouseWheelEvent& event) {
-  if (!host_)
-    return;
-
   if (event.deltaX != 0 || event.deltaY != 0)
     host_->ForwardWheelEvent(event);
 }
 
 gfx::Point RenderWidgetHostViewChildFrame::TransformPointToRootCoordSpace(
     const gfx::Point& point) {
   if (!frame_connector_)
     return point;
 
   return frame_connector_->TransformPointToRootCoordSpace(point, surface_id_);
@@ skipping 132 matching lines @@
       BrowserAccessibilityManager::GetEmptyDocument(), delegate);
 }
 
 void RenderWidgetHostViewChildFrame::ClearCompositorSurfaceIfNecessary() {
   if (surface_factory_ && !surface_id_.is_null())
     surface_factory_->Destroy(surface_id_);
   surface_id_ = cc::SurfaceId();
 }
 
 }  // namespace content