Remove observer when removing delegate, in Instant.

chrome/browser/instant/instant_loader.cc

 // 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 "chrome/browser/instant/instant_loader.h"
 
 #include "chrome/browser/content_settings/tab_specific_content_settings.h"
 #include "chrome/browser/history/history_types.h"
 #include "chrome/browser/instant/instant_loader_delegate.h"
 #include "chrome/browser/profiles/profile.h"
@@ skipping 182 matching lines @@
                         OnInstantSupportDetermined)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
 }
 
 void InstantLoader::WebContentsDelegateImpl::OnSetSuggestions(
     int page_id,
     const std::vector<string16>& suggestions,
     InstantCompleteBehavior behavior) {
+  DCHECK(loader_->preview_contents() &&
+         loader_->preview_contents_->web_contents());
+  // TODO(sreeram): Remove this 'if' bandaid once bug 141875 is confirmed fixed.
+  if (!loader_->preview_contents() ||
+      !loader_->preview_contents_->web_contents()) {
+    return;
+  }
   content::NavigationEntry* entry = loader_->preview_contents_->web_contents()->
                                         GetController().GetActiveEntry();
   if (entry && page_id == entry->GetPageID()) {
     MaybeSetAndNotifyInstantSupportDetermined(true);
     loader_->loader_delegate_->SetSuggestions(loader_, suggestions, behavior);
   }
 }
 
 void InstantLoader::WebContentsDelegateImpl::OnInstantSupportDetermined(
     int page_id,
     bool result) {
+  DCHECK(loader_->preview_contents() &&
+         loader_->preview_contents_->web_contents());
+  // TODO(sreeram): Remove this 'if' bandaid once bug 141875 is confirmed fixed.
+  if (!loader_->preview_contents() ||
+      !loader_->preview_contents_->web_contents()) {
+    return;
+  }
   content::NavigationEntry* entry = loader_->preview_contents_->web_contents()->
                                         GetController().GetActiveEntry();
   if (entry && page_id == entry->GetPageID())
     MaybeSetAndNotifyInstantSupportDetermined(result);
 }
 
 
 void InstantLoader::WebContentsDelegateImpl
     ::CommitFromPointerReleaseIfNecessary() {
   if (is_pointer_down_from_activate_) {
     is_pointer_down_from_activate_ = false;
     loader_->loader_delegate_->CommitInstantLoader(loader_);
   }
 }
 
 void InstantLoader::WebContentsDelegateImpl
     ::MaybeSetAndNotifyInstantSupportDetermined(bool supports_instant) {
   // If we already determined that the loader supports Instant, nothing to do.
   if (loader_->supports_instant_)
     return;
 
   loader_->supports_instant_ = supports_instant;
   loader_->loader_delegate_->InstantSupportDetermined(loader_,
                                                       supports_instant);
 
   // If the page doesn't support the Instant API, InstantController schedules

[sky, 2012/08/10 22:35:39]

Can we move this above 250? Seem dangerous to do things after calling out.

[sreeram, 2012/08/10 22:38:48]

Done.

   // the loader for destruction. Stop sending the controller any more messages,
   // by severing the connection from the WebContents to us (its delegate).
-  if (!supports_instant)
+  if (!supports_instant) {
     loader_->preview_contents_->web_contents()->SetDelegate(NULL);
+    Observe(NULL);
+  }
 }
 
 // InstantLoader ---------------------------------------------------------------
 
 InstantLoader::InstantLoader(InstantLoaderDelegate* delegate,
                              const std::string& instant_url,
                              const TabContents* tab_contents)
     : loader_delegate_(delegate),
       preview_contents_(new TabContents(content::WebContents::Create(
           tab_contents->profile(), NULL, MSG_ROUTING_NONE,
           tab_contents->web_contents(),
           tab_contents->web_contents()->GetController().
                                         GetSessionStorageNamespace()))),
-      preview_delegate_(new WebContentsDelegateImpl(
-          ALLOW_THIS_IN_INITIALIZER_LIST(this))),
       supports_instant_(false),
       instant_url_(instant_url) {
 }
 
 InstantLoader::~InstantLoader() {
   if (preview_contents())
     preview_contents_->web_contents()->SetDelegate(NULL);
 }
 
 void InstantLoader::Init() {
@@ skipping 47 matching lines @@
       rwhv->SetTakesFocusOnlyOnMouseDown(true);
     }
     return;
   }
   NOTREACHED();
 #endif
 }
 
 void InstantLoader::SetupPreviewContents() {
   content::WebContents* new_contents = preview_contents_->web_contents();
+  preview_delegate_.reset(new WebContentsDelegateImpl(this));
   WebContentsDelegateImpl* new_delegate = preview_delegate_.get();
   new_contents->SetDelegate(new_delegate);
 
   // Disable popups and such (mainly to avoid losing focus and reverting the
   // preview prematurely).
   preview_contents_->blocked_content_tab_helper()->SetAllContentsBlocked(true);
   preview_contents_->constrained_window_tab_helper()->set_delegate(
                                                           new_delegate);
   preview_contents_->content_settings()->SetPopupsBlocked(true);
   preview_contents_->core_tab_helper()->set_delegate(new_delegate);
@@ skipping 10 matching lines @@
   }
   registrar_.Add(this, content::NOTIFICATION_RENDER_VIEW_HOST_CHANGED,
                  content::Source<content::NavigationController>(
                      &new_contents->GetController()));
 #endif
 }
 
 void InstantLoader::CleanupPreviewContents() {
   content::WebContents* old_contents = preview_contents_->web_contents();
   old_contents->SetDelegate(NULL);
+  preview_delegate_.reset();
 
   preview_contents_->blocked_content_tab_helper()->SetAllContentsBlocked(false);
   preview_contents_->constrained_window_tab_helper()->set_delegate(NULL);
   preview_contents_->content_settings()->SetPopupsBlocked(false);
   preview_contents_->core_tab_helper()->set_delegate(NULL);
   if (ThumbnailGenerator* tg = preview_contents_->thumbnail_generator())
     tg->set_enabled(true);
 
 #if defined(OS_MACOSX)
   if (content::RenderWidgetHostView* rwhv =
@@ skipping 10 matching lines @@
                                            TabContents* new_tc) {
   DCHECK(old_tc == preview_contents_);
   CleanupPreviewContents();
   // We release here without deleting so that the caller still has the
   // responsibility for deleting the TabContents.
   ignore_result(preview_contents_.release());
   preview_contents_.reset(new_tc);
   SetupPreviewContents();
   loader_delegate_->SwappedTabContents(this);
 }