Centralize logic around Instant modes.

chrome/browser/instant/instant_controller.h

Index: chrome/browser/instant/instant_controller.h
diff --git a/chrome/browser/instant/instant_controller.h b/chrome/browser/instant/instant_controller.h
index 242466731d88fd70a3f9db86afc97537cf8a7324..b1557f8031f847774349355d7f2ce452920006f6 100644
--- a/chrome/browser/instant/instant_controller.h
+++ b/chrome/browser/instant/instant_controller.h
@@ -50,6 +50,8 @@ class InstantController : public InstantLoaderDelegate {
   static const int kInlineAutocompleteFadeInTimeMS = 300;
 
   // InstantController may operate in one of these modes:
+  //   EXTENDED: Similar to INSTANT, but with extended functionality, such as

[Peter Kasting, 2012/08/31 01:51:19]

Nit: Might make sense to write the full description here and then have "INSTANT"
say "like EXTENDED, but without XXX".  Or, put EXTENDED just after INSTANT.

[sreeram, 2012/09/04 17:42:16]

Done.

+  //       rendering suggestions within the preview and previews of URLs.
   //   INSTANT: The default search engine is preloaded when the omnibox gets
   //       focus. Queries are issued as the user types. Predicted queries are
   //       inline autocompleted into the omnibox. Result previews are shown.
@@ -57,25 +59,37 @@ class InstantController : public InstantLoaderDelegate {
   //   HIDDEN: Same as SUGGEST, without the inline autocompletion.
   //   SILENT: Same as HIDDEN, without issuing queries as the user types. The
   //       query is sent only after the user presses <Enter>.
-  //   EXTENDED: Similar to INSTANT, but with extended functionality, such as
-  //       rendering suggestions within the preview and previews of URLs.
+  //   DISABLED: Instant is disabled.
   enum Mode {
+    EXTENDED,
     INSTANT,
     SUGGEST,
     HIDDEN,
     SILENT,
-    EXTENDED,
+    DISABLED,
   };
 
-  InstantController(InstantControllerDelegate* delegate, Mode mode);
   virtual ~InstantController();
 
+  // Creates a new InstantController. Caller owns the returned object. The
+  // |profile| pointer is not cached, so the underlying object need not live
+  // beyond this call. ***NOTE***: May return NULL, which means that Instant is
+  // disabled in this profile.

[Peter Kasting, 2012/08/31 01:51:19]

Is it legal to call this multiple times on the same profile?

If not, this API seems a bit prone to misuse... should the InstantController
become a full-fledged ProfileKeyedService?  That seems like it might be a lot
more standard to how most Chrome services work.

[sreeram, 2012/09/04 17:42:16]

Yes, it's legal to call it multiple times. I think the name and comments make it
clear that each invocation results in a new InstantController object being
created (and returned to the caller who then owns it).

+  static InstantController* CreateInstant(Profile* profile,
+                                          InstantControllerDelegate* delegate);
+
+  // Returns true if Instant is enabled and supports the extended API.
+  static bool IsExtendedAPIEnabled(Profile* profile);
+
+  // Returns true if Instant is enabled in a visible, preview-showing mode.
+  static bool IsInstantEnabled(Profile* profile);
+
+  // Returns true if Instant will provide autocomplete suggestions.
+  static bool IsSuggestEnabled(Profile* profile);
+
   // Registers Instant related preferences.
   static void RegisterUserPrefs(PrefService* prefs);
 
-  // Returns true if Instant is enabled for the given |profile|.
-  static bool IsEnabled(Profile* profile);
-
   // Invoked as the user types into the omnibox. |user_text| is what the user
   // has typed. |full_text| is what the omnibox is showing. These may differ if
   // the user typed only some text, and the rest was inline autocompleted. If
@@ -155,6 +169,8 @@ class InstantController : public InstantLoaderDelegate {
  private:
   FRIEND_TEST_ALL_PREFIXES(InstantTest, InstantLoaderRefresh);
 
+  InstantController(InstantControllerDelegate* delegate, Mode mode);
+
   // Creates a new loader if necessary (for example, if the |instant_url| has
   // changed since the last time we created the loader).
   void ResetLoader(const std::string& instant_url,