Use ThreadSafeSender in a couple of places.

content/common/fileapi/webblobregistry_impl.h

Index: content/common/fileapi/webblobregistry_impl.h
===================================================================
--- content/common/fileapi/webblobregistry_impl.h	(revision 184814)
+++ content/common/fileapi/webblobregistry_impl.h	(working copy)
@@ -5,6 +5,7 @@
 #ifndef CONTENT_COMMON_FILEAPI_WEBBLOBREGISTRY_IMPL_H_
 #define CONTENT_COMMON_FILEAPI_WEBBLOBREGISTRY_IMPL_H_
 
+#include "base/memory/ref_counted.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebBlobRegistry.h"
 
 namespace WebKit {
@@ -13,14 +14,13 @@
 }
 
 namespace content {
-class ChildThread;
+class ThreadSafeSender;
 
 class WebBlobRegistryImpl : public WebKit::WebBlobRegistry {
  public:
-  explicit WebBlobRegistryImpl(ChildThread* child_thread);
+  explicit WebBlobRegistryImpl(ThreadSafeSender* sender);
   virtual ~WebBlobRegistryImpl();
 
-  // See WebBlobRegistry.h for documentation on these functions.
   virtual void registerBlobURL(const WebKit::WebURL& url,
                                WebKit::WebBlobData& data);
   virtual void registerBlobURL(const WebKit::WebURL& url,
@@ -28,7 +28,7 @@
   virtual void unregisterBlobURL(const WebKit::WebURL& url);
 
  private:
-  ChildThread* child_thread_;
+  scoped_refptr<ThreadSafeSender> sender_;
 };
 
 }  // namespace content