Implement a ResourceThrottle for URL overriding in Chrome on Android.

content/browser/renderer_host/resource_dispatcher_host_impl.h

Index: content/browser/renderer_host/resource_dispatcher_host_impl.h
diff --git a/content/browser/renderer_host/resource_dispatcher_host_impl.h b/content/browser/renderer_host/resource_dispatcher_host_impl.h
index 22276e6ed331cb079e1f5b922271196b4dcff9f4..e556485ab3f39c62954d16e72d05963a9138c261 100644
--- a/content/browser/renderer_host/resource_dispatcher_host_impl.h
+++ b/content/browser/renderer_host/resource_dispatcher_host_impl.h
@@ -120,6 +120,10 @@ class CONTENT_EXPORT ResourceDispatcherHostImpl
                      int request_id,
                      bool from_renderer);
 
+  // If the request still exists it is marked as canceled with a
+  // HANDLED_EXTERNALLY status.
+  void CancelRequestWithHandledExternallyStatus(int child_id, int request_id);
+
   // Follows a deferred redirect for the given request.
   // new_first_party_for_cookies, if non-empty, is the new cookie policy URL
   // for the redirected URL.  If the cookie policy URL needs changing, pass
@@ -324,10 +328,20 @@ class CONTENT_EXPORT ResourceDispatcherHostImpl
   // Helper function for regular and download requests.
   void BeginRequestInternal(net::URLRequest* request);
 
+  // Helper function that resolves the request for the given (child_id,
+  // request_id) pair, cancels that request and posts a completion notification
+  // for the request if needed.
+  void CancelRequestWorker(int child_id,
+                           int request_id,
+                           bool from_renderer,
+                           bool handled_externally);
+
   // Helper function that cancels |request|.  Returns whether the
   // request was actually cancelled.  If a renderer cancels a request
   // for a download, we ignore the cancellation.
-  bool CancelRequestInternal(net::URLRequest* request, bool from_renderer);
+  bool CancelRequestInternal(net::URLRequest* request,
+                             bool from_renderer,
+                             bool handled_externally);
 
   // Updates the "cost" of outstanding requests for |child_id|.
   // The "cost" approximates how many bytes are consumed by all the in-memory