Move Translate browser-side IPC handling to the component.

chrome/browser/ui/browser.cc

 // Copyright 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/ui/browser.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
 #include <shellapi.h>
 #endif  // defined(OS_WIN)
@@ skipping 2225 matching lines @@
   // WebContents...
   web_contents->SetDelegate(delegate);
 
   // ...and all the helpers.
   BookmarkTabHelper::FromWebContents(web_contents)->set_delegate(delegate);
   WebContentsModalDialogManager::FromWebContents(web_contents)->
       SetDelegate(delegate);
   CoreTabHelper::FromWebContents(web_contents)->set_delegate(delegate);
   SearchEngineTabHelper::FromWebContents(web_contents)->set_delegate(delegate);
   SearchTabHelper::FromWebContents(web_contents)->set_delegate(delegate);
-  if (delegate)
+  translate::ContentTranslateDriver& content_translate_driver =
+      ChromeTranslateClient::FromWebContents(web_contents)->translate_driver();
+  if (delegate) {

[Takashi Toyoshima, 2014/09/16 06:32:47]

This is not your change, but using set_delegate inside the if () looks clearer.

     ZoomController::FromWebContents(web_contents)->AddObserver(this);
-  else
+    content_translate_driver.AddObserver(translate_driver_observer_.get());
+  } else {
     ZoomController::FromWebContents(web_contents)->RemoveObserver(this);
-  ChromeTranslateClient* chrome_translate_client =
-      ChromeTranslateClient::FromWebContents(web_contents);
-  chrome_translate_client->translate_driver().set_observer(
-      delegate ? delegate->translate_driver_observer_.get() : NULL);
+    content_translate_driver.RemoveObserver(translate_driver_observer_.get());
+  }
 }
 
 void Browser::CloseFrame() {
   window_->Close();
 }
 
 void Browser::TabDetachedAtImpl(content::WebContents* contents,
                                 int index,
                                 DetachType type) {
   if (type == DETACH_TYPE_DETACH) {
@@ skipping 208 matching lines @@
   if (contents && !allow_js_access) {
     contents->web_contents()->GetController().LoadURL(
         target_url,
         content::Referrer(),
         content::PAGE_TRANSITION_LINK,
         std::string());  // No extra headers.
   }
 
   return contents != NULL;
 }