Remove use of WebContentsImpl from ResourceDispatcherHostImpl

content/browser/loader/resource_dispatcher_host_impl.h

Index: content/browser/loader/resource_dispatcher_host_impl.h
diff --git a/content/browser/loader/resource_dispatcher_host_impl.h b/content/browser/loader/resource_dispatcher_host_impl.h
index 646fc2a3d940b313a2df00e41eee4180844df300..89c20a582fea068823565676843120ed531b1b4e 100644
--- a/content/browser/loader/resource_dispatcher_host_impl.h
+++ b/content/browser/loader/resource_dispatcher_host_impl.h
@@ -70,7 +70,6 @@ class ResourceMessageFilter;
 class ResourceRequestInfoImpl;
 class SaveFileManager;
 class ServiceWorkerNavigationHandleCore;
-class WebContentsImpl;
 struct CommonNavigationParams;
 struct DownloadSaveInfo;
 struct NavigationRequestInfo;
@@ -217,7 +216,7 @@ class CONTENT_EXPORT ResourceDispatcherHostImpl
   // Force cancels any pending requests for the given process.
   void CancelRequestsForProcess(int child_id);
 
-  void OnUserGesture(WebContentsImpl* contents);
+  void OnUserGesture();
 
   // Retrieves a net::URLRequest.  Must be called from the IO thread.
   net::URLRequest* GetURLRequest(const GlobalRequestID& request_id);
@@ -307,6 +306,9 @@ class CONTENT_EXPORT ResourceDispatcherHostImpl
   // or experiment status. For unit tests only.
   void EnableStaleWhileRevalidateForTesting();
 
+  // Sets the LoaderDelegate, which much outlive this object. Ownership is not
+  // transferred. The LoaderDelegate should be interacted with asynchronously,
+  // and on the IO thread.

[mmenke, 2016/06/29 22:05:20]

Not sure what you mean by "asynchronously".  If you mean the LoaderDelegate
shouldn't block tasks, that seems a propertly of the delegate's API, not the RDH
method to set it.

[scottmg, 2016/06/29 22:16:19]

I was trying to get across that it should eventually represent talking to
another process, but you're right that that's a property of the delegate api
(e.g. shouldn't have methods that return the values of computations), so removed
here.

   void SetLoaderDelegate(LoaderDelegate* loader_delegate);
 
  private: