Move instant support to SearchTabHelper.

chrome/browser/ui/browser_instant_controller.cc

 // Copyright 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/ui/browser_instant_controller.h"
 
 #include "base/bind.h"
 #include "base/prefs/pref_service.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_web_ui.h"
@@ skipping 249 matching lines @@
       !chrome::IsInstantCheckboxEnabled(profile());
   instant_.SetInstantEnabled(instant_checkbox_checked, use_local_overlay_only);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // BrowserInstantController, SearchModelObserver implementation:
 
 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;
 
   if (chrome::IsInstantExtendedAPIEnabled()) {
     // Record some actions corresponding to the mode change. Note that to get
     // the full story, it's necessary to look at other UMA actions as well,
     // such as tab switches.
     if (new_mode.is_search_results())
       content::RecordAction(UserMetricsAction("InstantExtended.ShowSRP"));
     else if (new_mode.is_ntp())
       content::RecordAction(UserMetricsAction("InstantExtended.ShowNTP"));
   }
 
   // If mode is now |NTP|, send theme-related information to Instant.
   if (new_mode.is_ntp())
     UpdateThemeInfo();
 
   instant_.SearchModeChanged(old_state.mode, new_mode);

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

Likewise, we probably don't want all of this function to run if only the instant
support bit changed.

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

Done.

 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // BrowserInstantController, content::NotificationObserver implementation:
 
 void BrowserInstantController::Observe(
     int type,
     const content::NotificationSource& source,
     const content::NotificationDetails& details) {
 #if defined(ENABLE_THEMES)
@@ skipping 120 matching lines @@
     if (!instant_service->IsInstantProcess(
             contents->GetRenderProcessHost()->GetID()))
       continue;
 
     // Reload the contents to ensure that it gets assigned to a non-priviledged
     // renderer.
     contents->GetController().Reload(false);
   }
   instant_.OnDefaultSearchProviderChanged();
 }