Refactor RenderWidgetHost::set_paint_observer()

chrome/browser/tab_contents/thumbnail_generator.cc

 // Copyright (c) 2009 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 "chrome/browser/tab_contents/thumbnail_generator.h"
 
 #include <algorithm>
 #include <map>
 
 #include "base/metrics/histogram.h"
@@ skipping 154 matching lines @@
                    NotificationService::AllSources());
     registrar_.Add(this, NotificationType::RENDER_WIDGET_VISIBILITY_CHANGED,
                    NotificationService::AllSources());
     registrar_.Add(this, NotificationType::RENDER_WIDGET_HOST_DESTROYED,
                    NotificationService::AllSources());
     registrar_.Add(this, NotificationType::TAB_CONTENTS_DISCONNECTED,
                    NotificationService::AllSources());
   }
 }
 
+void ThumbnailGenerator::MonitorRenderer(RenderWidgetHost* renderer,
+                                         bool monitor) {
+  Source<RenderWidgetHost> renderer_source = Source<RenderWidgetHost>(renderer);
+  bool currently_monitored =
+      registrar_.IsRegistered(
+        this,
+        NotificationType::RENDER_WIDGET_HOST_WILL_DESTROY_BACKING_STORE,
+        renderer_source);
+  if (monitor |= currently_monitored) {

[Nico, 2011/01/18 00:39:52]

Is this supposed to be != (it's currently |=)?

This makes stuff dcheck in Add() with tabpose on mac.

+    if (monitor) {
+      registrar_.Add(
+          this,
+          NotificationType::RENDER_WIDGET_HOST_WILL_DESTROY_BACKING_STORE,
+          renderer_source);
+      registrar_.Add(
+          this,
+          NotificationType::RENDER_WIDGET_HOST_DID_UPDATE_BACKING_STORE,
+          renderer_source);
+      registrar_.Add(
+          this,
+          NotificationType::RENDER_WIDGET_HOST_DID_RECEIVE_PAINT_AT_SIZE_ACK,
+          renderer_source);
+    } else {
+      registrar_.Remove(
+          this,
+          NotificationType::RENDER_WIDGET_HOST_WILL_DESTROY_BACKING_STORE,
+          renderer_source);
+      registrar_.Remove(
+          this,
+          NotificationType::RENDER_WIDGET_HOST_DID_UPDATE_BACKING_STORE,
+          renderer_source);
+      registrar_.Remove(
+          this,
+          NotificationType::RENDER_WIDGET_HOST_DID_RECEIVE_PAINT_AT_SIZE_ACK,
+          renderer_source);
+    }
+  }
+}
+
 void ThumbnailGenerator::AskForSnapshot(RenderWidgetHost* renderer,
                                         bool prefer_backing_store,
                                         ThumbnailReadyCallback* callback,
                                         gfx::Size page_size,
                                         gfx::Size desired_size) {
   if (prefer_backing_store) {
     BackingStore* backing_store = renderer->GetBackingStore(false);
     if (backing_store) {
       // We were able to find a non-null backing store for this renderer, so
       // we'll go with it.
@@ skipping 164 matching lines @@
   }
 }
 
 void ThumbnailGenerator::Observe(NotificationType type,
                                  const NotificationSource& source,
                                  const NotificationDetails& details) {
   switch (type.value) {
     case NotificationType::RENDER_VIEW_HOST_CREATED_FOR_TAB: {
       // Install our observer for all new RVHs.
       RenderViewHost* renderer = Details<RenderViewHost>(details).ptr();
-      renderer->set_painting_observer(this);
+      MonitorRenderer(renderer, true);
       break;
     }
 
     case NotificationType::RENDER_WIDGET_VISIBILITY_CHANGED:
       if (*Details<bool>(details).ptr())
         WidgetShown(Source<RenderWidgetHost>(source).ptr());
       else
         WidgetHidden(Source<RenderWidgetHost>(source).ptr());
       break;
 
     case NotificationType::RENDER_WIDGET_HOST_DESTROYED:
       WidgetDestroyed(Source<RenderWidgetHost>(source).ptr());
       break;
 
+    case NotificationType::RENDER_WIDGET_HOST_WILL_DESTROY_BACKING_STORE:
+      WidgetWillDestroyBackingStore(
+          Source<RenderWidgetHost>(source).ptr(),
+          Details<BackingStore>(details).ptr());
+      break;
+
+    case NotificationType::RENDER_WIDGET_HOST_DID_UPDATE_BACKING_STORE:
+      WidgetDidUpdateBackingStore(Source<RenderWidgetHost>(source).ptr());
+      break;
+
+    case NotificationType::RENDER_WIDGET_HOST_DID_RECEIVE_PAINT_AT_SIZE_ACK: {
+      RenderWidgetHost::PaintAtSizeAckDetails* size_ack_details =
+          Details<RenderWidgetHost::PaintAtSizeAckDetails>(details).ptr();
+      WidgetDidReceivePaintAtSizeAck(
+          Source<RenderWidgetHost>(source).ptr(),
+          size_ack_details->tag,
+          size_ack_details->size);
+      break;
+    }
+
     case NotificationType::TAB_CONTENTS_DISCONNECTED:
       TabContentsDisconnected(Source<TabContents>(source).ptr());
       break;
 
     default:
       NOTREACHED();
   }
 }
 
 void ThumbnailGenerator::WidgetShown(RenderWidgetHost* widget) {
@@ skipping 84 matching lines @@
                  &ThumbnailGenerator::ShownDelayHandler);
   }
 }
 
 void ThumbnailGenerator::EraseHostFromShownList(RenderWidgetHost* widget) {
   std::vector<RenderWidgetHost*>::iterator found =
       std::find(shown_hosts_.begin(), shown_hosts_.end(), widget);
   if (found != shown_hosts_.end())
     shown_hosts_.erase(found);
 }