Move instant support to SearchTabHelper.

chrome/browser/ui/browser_instant_controller.cc

Index: chrome/browser/ui/browser_instant_controller.cc
diff --git a/chrome/browser/ui/browser_instant_controller.cc b/chrome/browser/ui/browser_instant_controller.cc
index cacd42f622a36ad8629604cc05ffa81f678f4262..7a6e57d7928724f7e60726f603d185531caf91ab 100644
--- a/chrome/browser/ui/browser_instant_controller.cc
+++ b/chrome/browser/ui/browser_instant_controller.cc
@@ -267,7 +267,8 @@ void BrowserInstantController::ResetInstant(const std::string& pref_name) {
 void BrowserInstantController::ModelChanged(
     const SearchModel::State& old_state,
     const SearchModel::State& new_state) {
-  if (old_state.mode == new_state.mode)
+  if (old_state.mode == new_state.mode &&
+      old_state.instant_support == new_state.instant_support)

[samarth, 2013/06/14 00:17:10]

This is not strictly correct.  The code below assume that the _mode_ changed, so
for example, this could mess up uma metrics.  I think you want something like
if (old_mode != new_mode)
  SearchModeChanged()
if (old_support != new_support)
  InstantSupportChanged

[kmadhusu, 2013/06/17 16:49:19]

Good catch. Fixed.

     return;
 
   const SearchMode& new_mode = new_state.mode;