Make ChromeAutofillClient a ZoomObserver.

chrome/browser/ui/tab_helpers.cc

Index: chrome/browser/ui/tab_helpers.cc
diff --git a/chrome/browser/ui/tab_helpers.cc b/chrome/browser/ui/tab_helpers.cc
index a8d1d09311fa90c7e317240de89da569c4e5ac96..f696e5cb6b2f33aea6da737f165565d0ed72c157 100644
--- a/chrome/browser/ui/tab_helpers.cc
+++ b/chrome/browser/ui/tab_helpers.cc
@@ -165,6 +165,13 @@ void TabHelpers::AttachTabHelpers(WebContents* 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)