Implement exponential back-off mechanism and enforce it at the URLRequestHttpJob level.

chrome/common/net/url_fetcher.h

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // This file contains URLFetcher, a wrapper around URLRequest that handles
 // low-level details like thread safety, ref counting, and incremental buffer
 // reading.  This is useful for callers who simply want to get the data from a
 // URL and don't care about all the nitty-gritty details.
 //
 // NOTE(willchan): Only one "IO" thread is supported for URLFetcher.  This is a
@@ skipping 134 matching lines @@
   // Set the URLRequestContext on the request.  Must be called before the
   // request is started.
   void set_request_context(
       URLRequestContextGetter* request_context_getter);
 
   // If |retry| is false, 5xx responses will be propagated to the observer,
   // if it is true URLFetcher will automatically re-execute the request,
   // after backoff_delay() elapses. URLFetcher has it set to true by default.
   void set_automatically_retry_on_5xx(bool retry);
 
+  int max_retries() const { return max_retries_; }
+
+  void set_max_retries(int max_retries) { max_retries_ = max_retries; }
+
   // Returns the back-off delay before the request will be retried,
   // when a 5xx response was received.
   base::TimeDelta backoff_delay() const { return backoff_delay_; }
 
   // Sets the back-off delay, allowing to mock 5xx requests in unit-tests.
 #if defined(UNIT_TEST)
   void set_backoff_delay(base::TimeDelta backoff_delay) {
     backoff_delay_ = backoff_delay;
   }
 #endif  // defined(UNIT_TEST)
@@ skipping 31 matching lines @@
 
   static Factory* factory_;
 
   // If |automatically_retry_on_5xx_| is false, 5xx responses will be
   // propagated to the observer, if it is true URLFetcher will automatically
   // re-execute the request, after the back-off delay has expired.
   // true by default.
   bool automatically_retry_on_5xx_;
   // Back-off time delay. 0 by default.
   base::TimeDelta backoff_delay_;
+  // Maximum retris allowed.

[Jói, 2010/11/12 00:12:08]

retris -> retries

[yzshen, 2010/11/12 02:05:46]

Done.

+  int max_retries_;
 
   static bool g_interception_enabled;
 
   DISALLOW_COPY_AND_ASSIGN(URLFetcher);
 };
 
 #endif  // CHROME_COMMON_NET_URL_FETCHER_H_