Implement lifetime observer on RenderWidgetHostViewBase.

content/browser/renderer_host/render_widget_host_view_mac.mm

 // Copyright (c) 2012 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/renderer_host/render_widget_host_view_mac.h"
 
 #import <objc/runtime.h>
 #include <OpenGL/gl.h>
 #include <QuartzCore/QuartzCore.h>
 #include <stdint.h>
@@ skipping 545 matching lines @@
 
 RenderWidgetHostViewMac::~RenderWidgetHostViewMac() {
   gfx::Screen::GetScreen()->RemoveObserver(this);
 
   // This is being called from |cocoa_view_|'s destructor, so invalidate the
   // pointer.
   cocoa_view_ = nil;
 
   UnlockMouse();
 
-  if (render_widget_host_ && render_widget_host_->delegate() &&
-      render_widget_host_->delegate()->GetInputEventRouter()) {
-    render_widget_host_->delegate()
-        ->GetInputEventRouter()
-        ->RemoveSurfaceIdNamespaceOwner(GetSurfaceIdNamespace());
-  }
-
   // Ensure that the browser compositor is destroyed in a safe order.
   ShutdownBrowserCompositor();
 
   // We are owned by RenderWidgetHostViewCocoa, so if we go away before the
   // RenderWidgetHost does we need to tell it not to hold a stale pointer to
   // us.
   if (render_widget_host_) {
     // If this is a RenderWidgetHostViewGuest's platform_view_, we're not the
     // RWH's view, the RenderWidgetHostViewGuest is. So don't reset the RWH's
     // view, the RenderWidgetHostViewGuest will do it.
@@ skipping 466 matching lines @@
   composition_range_ = range;
   composition_bounds_ = character_bounds;
 }
 
 void RenderWidgetHostViewMac::RenderProcessGone(base::TerminationStatus status,
                                                 int error_code) {
   Destroy();
 }
 
 void RenderWidgetHostViewMac::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.
   [[NSNotificationCenter defaultCenter]
       removeObserver:cocoa_view_
                 name:NSWindowWillCloseNotification
               object:popup_window_];
 
   // We've been told to destroy.
   [cocoa_view_ retain];
   [cocoa_view_ removeFromSuperview];
   [cocoa_view_ autorelease];
 
   [popup_window_ close];
   popup_window_.autorelease();
 
   [fullscreen_window_manager_ exitFullscreenMode];
   fullscreen_window_manager_.reset();
   [pepper_fullscreen_window_ close];
 
   // This can be called as part of processing the window's responder
   // chain, for instance |-performKeyEquivalent:|.  In that case the
   // object needs to survive until the stack unwinds.
   pepper_fullscreen_window_.autorelease();
 
-  // Clear SurfaceID namespace ownership before we shutdown the
-  // compositor.
-  if (render_widget_host_ && render_widget_host_->delegate() &&
-      render_widget_host_->delegate()->GetInputEventRouter()) {
-    render_widget_host_->delegate()
-        ->GetInputEventRouter()
-        ->RemoveSurfaceIdNamespaceOwner(GetSurfaceIdNamespace());
-  }
-
   // Delete the delegated frame state, which will reach back into
   // render_widget_host_.
   ShutdownBrowserCompositor();
 
+  // Make sure none of our observers send events for us to process after
+  // we release render_widget_host_.
+  NotifyObserversAboutShutdown();
+
   // We get this call just before |render_widget_host_| deletes
   // itself.  But we are owned by |cocoa_view_|, which may be retained
   // by some other code.  Examples are WebContentsViewMac's
   // |latent_focus_view_| and TabWindowController's
   // |cachedContentView_|.
   render_widget_host_ = NULL;
 }
 
 // Called from the renderer to tell us what the tooltip text should be. It
 // calls us frequently so we need to cache the value to prevent doing a lot
@@ skipping 2341 matching lines @@
 
 // "-webkit-app-region: drag | no-drag" is implemented on Mac by excluding
 // regions that are not draggable. (See ControlRegionView in
 // native_app_window_cocoa.mm). This requires the render host view to be
 // draggable by default.
 - (BOOL)mouseDownCanMoveWindow {
   return YES;
 }
 
 @end