First cut at experimental API for managing installed/enabled extensions.

The documented methods should all be working, but events are not hooked up yet.

BUG=51178
TEST=none

Review URL: http://codereview.chromium.org/3200012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@57544 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/common/extensions/extension.h b/chrome/common/extensions/extension.h
index cad9059f..cad7dbd 100644
--- a/chrome/common/extensions/extension.h
+++ b/chrome/common/extensions/extension.h
@@ -173,7 +173,7 @@
   // NOTE: Static so that it can be used from multiple threads.
   static GURL GetResourceURL(const GURL& extension_url,
                              const std::string& relative_path);
-  GURL GetResourceURL(const std::string& relative_path) {
+  GURL GetResourceURL(const std::string& relative_path) const {
     return GetResourceURL(url(), relative_path);
   }