a little code cleanup for translate infobars

- use index of selected language menu item (which corresponds to index in array of languages) to check if selection has changed; was retrieving, converting and comparing text, which is more expensive and slower
- only call backend to translate when source and target languages are different

BUG=31297
TEST=verify that selection of languages in translate infobars still work as expected.
Review URL: http://codereview.chromium.org/563018

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@37979 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 8 insertions, 1 deletions

diff --git a/chrome/browser/translate/translate_infobars_delegates.cc b/chrome/browser/translate/translate_infobars_delegates.cc
index 3dba0ca..7bf2a4f 100644
--- a/chrome/browser/translate/translate_infobars_delegates.cc
+++ b/chrome/browser/translate/translate_infobars_delegates.cc
@@ -53,7 +53,8 @@ void TranslateInfoBarDelegate::GetAvailableTargetLanguages(
 }
 
 void TranslateInfoBarDelegate::Translate() {
-  tab_contents_->TranslatePage(original_lang_code(), target_lang_code());
+  if (original_lang_index_ != target_lang_index_)
+    tab_contents_->TranslatePage(original_lang_code(), target_lang_code());
 }
 
 bool TranslateInfoBarDelegate::IsLanguageBlacklisted() {
diff --git a/chrome/browser/translate/translate_infobars_delegates.h b/chrome/browser/translate/translate_infobars_delegates.h
index 18416c4..5b10f3f 100644
--- a/chrome/browser/translate/translate_infobars_delegates.h
+++ b/chrome/browser/translate/translate_infobars_delegates.h
@@ -28,6 +28,12 @@ class TranslateInfoBarDelegate : public InfoBarDelegate {
   virtual bool ShouldAlwaysTranslate();
   virtual void ToggleAlwaysTranslate();
 
+  int original_lang_index() const {
+    return original_lang_index_;
+  }
+  int target_lang_index() const {
+    return target_lang_index_;
+  }
   const std::string& original_lang_code() const {
     return supported_languages_[original_lang_index_];
   }