Centralize logic around Instant modes.

chrome/browser/instant/instant_controller.h

 // Copyright (c) 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.
 
 #ifndef CHROME_BROWSER_INSTANT_INSTANT_CONTROLLER_H_
 #define CHROME_BROWSER_INSTANT_INSTANT_CONTROLLER_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 32 matching lines @@
 // invoked on the delegate.
 class InstantController : public InstantLoaderDelegate {
  public:
   // Amount of time to wait before starting the animation for suggested text.
   static const int kInlineAutocompletePauseTimeMS = 1000;
 
   // Duration of the suggested text animation in which the colors change.
   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.
   //   SUGGEST: Same as INSTANT, without visible previews.
   //   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
   // |verbatim| is true, search results are shown for the exact omnibox text,
   // rather than the best guess as to what the user means. Returns true if the
   // update is accepted (i.e., if |match| is a search rather than a URL).
   bool Update(const AutocompleteMatch& match,
               const string16& user_text,
               const string16& full_text,
               bool verbatim);
@@ skipping 59 matching lines @@
 
 #if defined(UNIT_TEST)
   // Accessors used only in tests.
   bool is_showing() const { return is_showing_; }
   InstantLoader* loader() const { return loader_.get(); }
 #endif
 
  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,
                    const TabContents* active_tab);
 
   // Ensures that the |loader_| uses the default Instant URL, recreating it if
   // necessary. Will not do anything if the Instant URL could not be determined
   // or the active tab is NULL (browser is shutting down).
   void CreateDefaultLoader();
 
@@ skipping 83 matching lines @@
   // Search terms extraction (for autocomplete history matches) doesn't work
   // on Instant URLs. So, whenever the user commits an Instant search, we add
   // an equivalent non-Instant search URL to history, so that the search shows
   // up in autocomplete history matches.
   GURL url_for_history_;
 
   DISALLOW_COPY_AND_ASSIGN(InstantController);
 };
 
 #endif  // CHROME_BROWSER_INSTANT_INSTANT_CONTROLLER_H_