Move instant support to SearchTabHelper.

chrome/browser/ui/search/search_tab_helper.h

Index: chrome/browser/ui/search/search_tab_helper.h
diff --git a/chrome/browser/ui/search/search_tab_helper.h b/chrome/browser/ui/search/search_tab_helper.h
index 8dd771100bd814bded3345f691479189a6b21cb2..c9b52caec4b5a45f5c79500f3a0cee71a739ff04 100644
--- a/chrome/browser/ui/search/search_tab_helper.h
+++ b/chrome/browser/ui/search/search_tab_helper.h
@@ -9,6 +9,7 @@
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
+#include "base/gtest_prod_util.h"
 #include "chrome/browser/ui/search/search_model.h"
 #include "chrome/common/instant_types.h"
 #include "content/public/browser/notification_observer.h"
@@ -20,6 +21,8 @@ namespace content {
 class WebContents;
 }
 
+class InstantPageTest;
+
 // Per-tab search "helper".  Acts as the owner and controller of the tab's
 // search UI model.

[samarth, 2013/06/19 05:25:02]

I think this could a top-level comment of how instant support is tracked.  In
particular, how each new naventry (except for in-page navigations) reset support
to UNKNOWN and cause support to be determined again.

[kmadhusu, 2013/06/19 16:28:15]

Done.

 class SearchTabHelper : public content::NotificationObserver,
@@ -50,8 +53,23 @@ class SearchTabHelper : public content::NotificationObserver,
   bool UpdateLastKnownMostVisitedItems(
       const std::vector<InstantMostVisitedItem>& items);
 
+  // Invoked to update the instant support state.
+  void InstantSupportChanged(bool supports_instant);
+
+  // Returns true if the page supports instant. If the instant support state is
+  // not determined or if the page does not support instant returns false.
+  bool SupportsInstant() const;
+
  private:
   friend class content::WebContentsUserData<SearchTabHelper>;
+  friend class InstantPageTest;
+  FRIEND_TEST_ALL_PREFIXES(InstantPageTest,
+                           DetermineIfPageSupportsInstant_Local);
+  FRIEND_TEST_ALL_PREFIXES(InstantPageTest,
+                           DetermineIfPageSupportsInstant_NonLocal);
+  FRIEND_TEST_ALL_PREFIXES(InstantPageTest,
+                           PageURLDoesntBelongToInstantRenderer);
+  FRIEND_TEST_ALL_PREFIXES(InstantPageTest, PageSupportsInstant);
 
   explicit SearchTabHelper(content::WebContents* web_contents);
 
@@ -62,10 +80,23 @@ class SearchTabHelper : public content::NotificationObserver,
 
   // Overridden from contents::WebContentsObserver:
   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
+  virtual void DidFinishLoad(
+      int64 frame_id,
+      const GURL& validated_url,
+      bool is_main_frame,
+      content::RenderViewHost* render_view_host) OVERRIDE;
 
   // Sets the mode of the model based on the current URL of web_contents().
   void UpdateMode();
 
+  // Tells the renderer to determine if the page supports the Instant API, which
+  // results in a call to OnInstantSupportDetermined() when the reply
+  // is received.
+  void DetermineIfPageSupportsInstant();
+
+  // Handler for when Instant support has been determined.
+  void OnInstantSupportDetermined(int page_id, bool supports_instant);
+
   // Handlers for SearchBox API to show and hide top bars (bookmark and info
   // bars).
   void OnSearchBoxShowBars(int page_id);