Fix a crash caused by unknown saved language.

The language index in the dump referred by the crbug is left to -1, meaning that the language passed to TranslateInfoBarDelegate's constructor...

The call stack showed that the call came from an auto translate preference, so my only guess would be that a preference was saved for a language that is not available anymore, so I added code to protect against that.

BUG=93291
TEST=TranslateManagerTest.UnsupportedSavedLanguage

Review URL: http://codereview.chromium.org/7764003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@98661 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/translate/translate_infobar_delegate.cc

@@ -89,6 +89,7 @@ void TranslateInfoBarDelegate::SetOriginalLanguage(size_t language_index) {
 
 void TranslateInfoBarDelegate::SetTargetLanguage(size_t language_index) {
   DCHECK_LT(language_index, GetLanguageCount());
+  DCHECK_GE(language_index, 0U);
   target_language_index_ = language_index;
   if (infobar_view_)
     infobar_view_->TargetLanguageChanged();
@@ -348,6 +349,7 @@ TranslateInfoBarDelegate::TranslateInfoBarDelegate(
     if (language_code == target_language)
       target_language_index_ = iter - languages_.begin();
   }
+  DCHECK_NE(kNoIndex, target_language_index_);
 }
 
 bool TranslateInfoBarDelegate::ShouldExpire(

chrome/browser/translate/translate_manager.cc

@@ -489,8 +489,13 @@ void TranslateManager::InitiateTranslation(TabContents* tab,
   if (!tab->browser_context()->IsOffTheRecord() &&
       TranslatePrefs::ShouldAutoTranslate(prefs, language_code,
           &auto_target_lang)) {
-    TranslatePage(tab, language_code, auto_target_lang);
-    return;
+    // We need to confirm that the saved target language is still supported.
+    // Also, GetLanguageCode will take care of removing country code if any.
+    auto_target_lang = GetLanguageCode(auto_target_lang);
+    if (IsSupportedLanguage(auto_target_lang)) {
+      TranslatePage(tab, language_code, auto_target_lang);
+      return;
+    }
   }
 
   TabContentsWrapper* wrapper =