[Translate] Return before the new delegate is created if needed

chrome/browser/translate/translate_infobar_delegate.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/translate/translate_infobar_delegate.h"
 
 #include <algorithm>
 
 #include "base/i18n/string_compare.h"
 #include "base/metrics/histogram.h"
@@ skipping 49 matching lines @@
   }
 
   // Find any existing translate infobar delegate.
   TranslateInfoBarDelegate* old_delegate = NULL;
   for (size_t i = 0; i < infobar_service->infobar_count(); ++i) {
     old_delegate = infobar_service->infobar_at(i)->AsTranslateInfoBarDelegate();
     if (old_delegate)
       break;
   }
 
+  // Do not create the after translate infobar if we are auto translating.
+  if (infobar_type == TranslateInfoBarDelegate::AFTER_TRANSLATE ||
+      infobar_type == TranslateInfoBarDelegate::TRANSLATING) {
+      TranslateTabHelper* translate_tab_helper =
+          TranslateTabHelper::FromWebContents(infobar_service->web_contents());
+      if (!translate_tab_helper ||
+          translate_tab_helper->language_state().InTranslateNavigation()) {
+        DCHECK(!old_delegate);

[Takashi Toyoshima, 2013/07/17 17:02:08]

I agreed this DCHECK is always correct.
But I'd like to ask pkasting double checking this before submitting this CL.

[Peter Kasting, 2013/07/17 18:06:19]

I don't know whether the DCHECK here is important.  My instinct would be to
simplify this by omitting the DCHECK so you can move this block up above the
"find the old delegate" block as well.  I actually already did this in a local
change I hadn't gotten around to submitting yet.

+        return;
+      }
+  }
+
   // Create the new delegate.
   scoped_ptr<TranslateInfoBarDelegate> infobar(
       new TranslateInfoBarDelegate(infobar_type, error_type, infobar_service,
                                    prefs, shortcut_config,
                                    original_language, target_language));
   infobar->UpdateBackgroundAnimation(old_delegate);
 
-  // Do not create the after translate infobar if we are auto translating.
-  if (infobar_type == TranslateInfoBarDelegate::AFTER_TRANSLATE ||
-      infobar_type == TranslateInfoBarDelegate::TRANSLATING) {
-    TranslateTabHelper* translate_tab_helper =
-      TranslateTabHelper::FromWebContents(infobar_service->web_contents());
-    if (!translate_tab_helper ||
-         translate_tab_helper->language_state().InTranslateNavigation())
-      return;
-  }
-
   // Add the new delegate if necessary.
   if (!old_delegate) {
     infobar_service->AddInfoBar(infobar.PassAs<InfoBarDelegate>());
   } else if (replace_existing_infobar) {
     infobar_service->ReplaceInfoBar(old_delegate,
                                     infobar.PassAs<InfoBarDelegate>());
   }
 }
 
 void TranslateInfoBarDelegate::Translate() {
@@ skipping 316 matching lines @@
 
 TranslateInfoBarDelegate*
     TranslateInfoBarDelegate::AsTranslateInfoBarDelegate() {
   return this;
 }
 
 std::string TranslateInfoBarDelegate::GetPageHost() {
   NavigationEntry* entry = web_contents()->GetController().GetActiveEntry();
   return entry ? entry->GetURL().HostNoBrackets() : std::string();
 }