Make Platform::queryStorageUsageAndQuota work from worker threads

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 3b37e8755226191e1d485a5e8a33e2b9562503fb..173fa2f6545d2a69f4ed7b5b6ecabdc44bcdb973 100644
--- a/content/child/child_thread.h
+++ b/content/child/child_thread.h
@@ -37,6 +37,7 @@ class ChildHistogramMessageFilter;
 class ChildResourceMessageFilter;
 class FileSystemDispatcher;
 class QuotaDispatcher;
+class QuotaMessageFilter;
 class ResourceDispatcher;
 class SocketStreamDispatcher;
 class ThreadSafeSender;
@@ -112,6 +113,10 @@ class CONTENT_EXPORT ChildThread : public IPC::Listener, public IPC::Sender {
     return histogram_message_filter_.get();
   }
 
+  QuotaMessageFilter* quota_message_filter() const {
+    return quota_message_filter_.get();
+  }
+
   base::MessageLoop* message_loop() const { return message_loop_; }
 
   // Returns the one child thread. Can only be called on the main thread.
@@ -188,6 +193,8 @@ class CONTENT_EXPORT ChildThread : public IPC::Listener, public IPC::Sender {
 
   scoped_refptr<ChildResourceMessageFilter> resource_message_filter_;
 
+  scoped_refptr<QuotaMessageFilter> quota_message_filter_;
+
   base::WeakPtrFactory<ChildThread> channel_connected_factory_;
 
   // Observes the trace event system. When tracing is enabled, optionally