workers: Introduce a WorkerMessageFilter to ease routing/processing worker messages.

content/child/child_thread.h

Index: content/child/child_thread.h
diff --git a/content/child/child_thread.h b/content/child/child_thread.h
index 24cfc61f22cbbaf37a51e700b1764c09dee9240b..8ae3cc134ebae9165f9eb4737b17a4a070e86ff6 100644
--- a/content/child/child_thread.h
+++ b/content/child/child_thread.h
@@ -37,14 +37,13 @@ class WebFrame;
 }  // namespace blink
 
 namespace content {
-class BluetoothMessageFilter;
+class ChildMessageFilter;
 class ChildDiscardableSharedMemoryManager;
 class ChildGpuMemoryBufferManager;
 class ChildHistogramMessageFilter;
 class ChildResourceMessageFilter;
 class ChildSharedBitmapManager;
 class FileSystemDispatcher;
-class GeofencingMessageFilter;
 class NavigatorConnectDispatcher;
 class NotificationDispatcher;
 class PushDispatcher;
@@ -284,9 +283,8 @@ class CONTENT_EXPORT ChildThread : public IPC::Listener, public IPC::Sender {
 
   scoped_ptr<base::PowerMonitor> power_monitor_;
 
-  scoped_refptr<GeofencingMessageFilter> geofencing_message_filter_;
-
-  scoped_refptr<BluetoothMessageFilter> bluetooth_message_filter_;
+  scoped_refptr<ChildMessageFilter> geofencing_message_filter_;
+  scoped_refptr<ChildMessageFilter> bluetooth_message_filter_;
 
   scoped_refptr<NavigatorConnectDispatcher> navigator_connect_dispatcher_;