Make ChromeAutofillClient a ZoomObserver.

chrome/browser/ui/tab_helpers.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 "chrome/browser/ui/tab_helpers.h"
 
 #include "base/command_line.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/content_settings/tab_specific_content_settings.h"
 #include "chrome/browser/favicon/favicon_tab_helper.h"
@@ skipping 147 matching lines @@
   PDFTabHelper::CreateForWebContents(web_contents);
   PermissionBubbleManager::CreateForWebContents(web_contents);
   PluginObserver::CreateForWebContents(web_contents);
   SadTabHelper::CreateForWebContents(web_contents);
   safe_browsing::SafeBrowsingTabObserver::CreateForWebContents(web_contents);
   SearchEngineTabHelper::CreateForWebContents(web_contents);
   TabContentsSyncedTabDelegate::CreateForWebContents(web_contents);
   ThumbnailTabHelper::CreateForWebContents(web_contents);
   web_modal::WebContentsModalDialogManager::CreateForWebContents(web_contents);
   ZoomController::CreateForWebContents(web_contents);
+  // The ChromeAutofillClient is also a ZoomObserver, so we connect it to the
+  // ZoomController here. Since both are WebContentsObservers they cannot be
+  // dependant on their order of destruction: ZoomController silently clears
+  // its ZoomObserver list during WebContentsDestroyed() so there's no need
+  // for the ChromeAutofillClient to remove itself as an observer.
+  ZoomController::FromWebContents(web_contents)->AddObserver(
+      autofill::ChromeAutofillClient::FromWebContents(web_contents));

[Avi (use Gerrit), 2014/07/10 14:59:53]

:(

I would much rather move ZoomController before ChromeAutofillClient, and note
with a comment the dependency, than start calling code here.

The job of this file is to know what tab helpers need to be instantiated (and
unfortunately in what order). I'd prefer to keep the knowledge that the
ChromeAutofillClient needs to be a ZoomObserver inside ChromeAutofillClient.

 #endif
 
 #if defined(OS_WIN)
   MetroPinTabHelper::CreateForWebContents(web_contents);
 #endif
 
   // --- Feature tab helpers behind flags ---
 
 #if defined(ENABLE_CAPTIVE_PORTAL_DETECTION)
   CaptivePortalTabHelper::CreateForWebContents(web_contents);
@@ skipping 31 matching lines @@
   if (OneClickSigninHelper::CanOffer(web_contents,
                                      OneClickSigninHelper::CAN_OFFER_FOR_ALL,
                                      std::string(),
                                      NULL)) {
     OneClickSigninHelper::CreateForWebContentsWithPasswordManager(
         web_contents,
         ChromePasswordManagerClient::GetManagerFromWebContents(web_contents));
   }
 #endif
 }