Add mojo::StrongBindingSet and use it in GeolocationServiceContext.

content/browser/web_contents/web_contents_impl.h

Index: content/browser/web_contents/web_contents_impl.h
diff --git a/content/browser/web_contents/web_contents_impl.h b/content/browser/web_contents/web_contents_impl.h
index e78f43631f67b4ff5df604b3826edf60ed79abbc..815f4ede1af801c80b825a3d341fe4bb3de00ed6 100644
--- a/content/browser/web_contents/web_contents_impl.h
+++ b/content/browser/web_contents/web_contents_impl.h
@@ -50,7 +50,6 @@ class BrowserPluginEmbedder;
 class BrowserPluginGuest;
 class DateTimeChooserAndroid;
 class DownloadItem;
-class GeolocationServiceContext;
 class InterstitialPageImpl;
 class JavaScriptDialogManager;
 class ManifestManagerHost;
@@ -432,7 +431,6 @@ class CONTENT_EXPORT WebContentsImpl
   RenderFrameHost* GetGuestByInstanceID(
       RenderFrameHost* render_frame_host,
       int browser_plugin_instance_id) override;
-  GeolocationServiceContext* GetGeolocationServiceContext() override;
   WakeLockServiceContext* GetWakeLockServiceContext() override;
   void EnterFullscreenMode(const GURL& origin) override;
   void ExitFullscreenMode() override;
@@ -1301,8 +1299,6 @@ class CONTENT_EXPORT WebContentsImpl
   // Whether the last JavaScript dialog shown was suppressed. Used for testing.
   bool last_dialog_suppressed_;
 
-  scoped_ptr<GeolocationServiceContext> geolocation_service_context_;
-
   scoped_ptr<WakeLockServiceContext> wake_lock_service_context_;
 
   scoped_ptr<ScreenOrientationDispatcherHost>