Implement the 2016Q2 Translate UI designe spec out in

chrome/browser/translate/chrome_translate_client.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/translate/chrome_translate_client.h"
 
 #include <vector>
 
 #include "base/logging.h"
 #include "base/path_service.h"
@@ skipping 186 matching lines @@
         error_type,
         triggered_from_menu);
     return;
   }
 #endif
 
   // Bubble UI.
   if (step == translate::TRANSLATE_STEP_BEFORE_TRANSLATE) {
     // TODO(droger): Move this logic out of UI code.
     GetLanguageState().SetTranslateEnabled(true);
-    if (!GetLanguageState().HasLanguageChanged())
-      return;
+    if (!base::FeatureList::IsEnabled(translate::kTranslateUI2016Q2)) {

[msw, 2016/04/29 19:59:59]

nit: combine with nested if statement using &&...

[ftang, 2016/04/29 22:37:00]

Done.

+      if (!GetLanguageState().HasLanguageChanged())
+        return;
+    }
 
     if (!triggered_from_menu) {
       if (web_contents()->GetBrowserContext()->IsOffTheRecord())
         return;
       if (GetTranslatePrefs()->IsTooOftenDenied(source_language))
         return;
     }
   }
   ShowBubble(step, error_type);
 }
@@ skipping 121 matching lines @@
     if (GetLanguageState().InTranslateNavigation())
       return;
   }
 
   TranslateBubbleFactory::Show(
       browser->window(), web_contents(), step, error_type);
 #else
   NOTREACHED();
 #endif
 }