Add device location reporting

content/browser/geolocation/geolocation_provider.h

Index: content/browser/geolocation/geolocation_provider.h
diff --git a/content/browser/geolocation/geolocation_provider.h b/content/browser/geolocation/geolocation_provider.h
index a45a365f23066aa71491b65ce8aa07e7f05cb629..4286c11cf56a2a2b287ac3480209ad15196ca059 100644
--- a/content/browser/geolocation/geolocation_provider.h
+++ b/content/browser/geolocation/geolocation_provider.h
@@ -18,22 +18,22 @@ class GeolocationArbitrator;
 template<typename Type>
 struct DefaultSingletonTraits;
 
-// This is the main API to the geolocation subsystem. The application
-// will hold a single instance of this class, and can register multiple
-// observers which will be notified of location updates. Underlying location
-// arbitrator will only be enabled whilst there is at least one observer
-// registered.
+// This is the main API to the geolocation subsystem. The application will hold
+// a single instance of this class and can register multiple observers which
+// will be notified of location updates. The application must instantiate the
+// GeolocationProvider on the IO thread and must communicate with it on the same
+// thread.
+// The underlying location arbitrator will only be enabled whilst there is at
+// least one observer registered. The arbitrator and the location providers it
+// uses run on a separate Geolocation thread.
 class CONTENT_EXPORT GeolocationProvider
     : public base::Thread, public GeolocationObserver {
  public:
-  GeolocationProvider();
-
-  // Must be called from the same thread as the GeolocationProvider was created
-  // on. The GeolocationObserverOptions passed are used as a 'hint' for the
-  // provider preferences for this particular observer, however the observer
-  // could receive callbacks for best available locations from any active
-  // provider whilst it is registered.
-  // If an existing observer is added a second time it's options are updated
+  // The GeolocationObserverOptions passed are used as a 'hint' for the provider
+  // preferences for this particular observer, however the observer could
+  // receive callbacks for best available locations from any active provider
+  // whilst it is registered.
+  // If an existing observer is added a second time, its options are updated
   // but only a single call to RemoveObserver() is required to remove it.
   void AddObserver(GeolocationObserver* delegate,
                    const GeolocationObserverOptions& update_options);
@@ -49,18 +49,21 @@ class CONTENT_EXPORT GeolocationProvider
   virtual void OnLocationUpdate(const Geoposition& position) OVERRIDE;
 
   // Gets a pointer to the singleton instance of the location relayer, which
-  // is in turn bound to the browser's global context objects. Ownership is NOT
-  // returned.
+  // is in turn bound to the browser's global context objects. This must only be
+  // called on the IO thread so that the GeolocationProvider is always

[joth, 2012/04/23 10:05:14]

add a DCHECK for this?

[bartfab (slow), 2012/04/23 12:21:28]

There is a DCHECK in GetInstance() already. I put in the comment to explain why
it is there.

+  // instantiated on the same thread. Ownership is NOT returned.
   static GeolocationProvider* GetInstance();
 
   typedef std::map<GeolocationObserver*, GeolocationObserverOptions>
       ObserverMap;
 
- private:
+ protected:
   friend struct DefaultSingletonTraits<GeolocationProvider>;
+  GeolocationProvider();
   virtual ~GeolocationProvider();
 
-  bool OnClientThread() const;
+ private:
+  static bool OnIOThread();
   bool OnGeolocationThread() const;
 
   // When the observer list changes, we may start the thread and the required
@@ -85,9 +88,7 @@ class CONTENT_EXPORT GeolocationProvider
   virtual void Init() OVERRIDE;
   virtual void CleanUp() OVERRIDE;
 
-  scoped_refptr<base::MessageLoopProxy> client_loop_;
-
-  // Only used on client thread
+  // Only used on the IO thread
   ObserverMap observers_;
   bool is_permission_granted_;
   Geoposition position_;