Merge r21417 to 172....

net/url_request/url_request.h

Index: net/url_request/url_request.h
===================================================================
--- net/url_request/url_request.h	(revision 23600)
+++ net/url_request/url_request.h	(working copy)
@@ -103,10 +103,19 @@
     //
     // When this function is called, the request will still contain the
     // original URL, the destination of the redirect is provided in 'new_url'.
-    // If the request is not canceled the redirect will be followed and the
-    // request's URL will be changed to the new URL.
+    // If the delegate does not cancel the request and |*defer_redirect| is
+    // false, then the redirect will be followed, and the request's URL will be
+    // changed to the new URL.  Otherwise if the delegate does not cancel the
+    // request and |*defer_redirect| is true, then the redirect will be
+    // followed once FollowDeferredRedirect is called on the URLRequest.
+    //
+    // The caller must set |*defer_redirect| to false, so that delegates do not
+    // need to set it if they are happy with the default behavior of not
+    // deferring redirect.
     virtual void OnReceivedRedirect(URLRequest* request,
-                                    const GURL& new_url) = 0;
+                                    const GURL& new_url,
+                                    bool* defer_redirect) {
+    }
 
     // Called when we receive an authentication failure.  The delegate should
     // call request->SetAuth() with the user's credentials once it obtains them,
@@ -397,6 +406,10 @@
   // will be set to an error.
   bool Read(net::IOBuffer* buf, int max_bytes, int *bytes_read);
 
+  // This method may be called to follow a redirect that was deferred in
+  // response to an OnReceivedRedirect call.
+  void FollowDeferredRedirect();
+
   // One of the following two methods should be called in response to an
   // OnAuthRequired() callback (and only then).
   // SetAuth will reissue the request with the given credentials.