Implement a simple Extension App Omnibox provider.

chrome/browser/autocomplete/autocomplete_match.h

Index: chrome/browser/autocomplete/autocomplete_match.h
===================================================================
--- chrome/browser/autocomplete/autocomplete_match.h	(revision 80603)
+++ chrome/browser/autocomplete/autocomplete_match.h	(working copy)
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -128,10 +128,10 @@
   // no provider (or memory of the user's selection).
   AutocompleteProvider* provider;
 
-  // The relevance of this match. See table above for scores returned by
-  // various providers. This is used to rank matches among all responding
-  // providers, so different providers must be carefully tuned to supply
-  // matches with appropriate relevance.
+  // The relevance of this match. See table in autocomplete.h for scores
+  // returned by various providers. This is used to rank matches among all
+  // responding providers, so different providers must be carefully tuned to
+  // supply matches with appropriate relevance.
   //
   // TODO(pkasting): http://b/1111299 This should be calculated algorithmically,
   // rather than being a fairly fixed value defined by the table above.