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

net/net.gyp

 # 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'targets': [
     {
@@ skipping 634 matching lines @@
         'spdy/spdy_session.cc',
         'spdy/spdy_session.h',
         'spdy/spdy_session_pool.cc',
         'spdy/spdy_session_pool.h',
         'spdy/spdy_settings_storage.cc',
         'spdy/spdy_settings_storage.h',
         'spdy/spdy_stream.cc',
         'spdy/spdy_stream.h',
         'url_request/https_prober.h',
         'url_request/https_prober.cc',
+        'url_request/request_throttler_entry.cc',
+        'url_request/request_throttler_entry.h',
+        'url_request/request_throttler_entry_interface.h',
+        'url_request/request_throttler_header_adapter.h',
+        'url_request/request_throttler_header_adapter.cc',
+        'url_request/request_throttler_header_interface.h',
+        'url_request/request_throttler_manager.cc',
+        'url_request/request_throttler_manager.h',
         'url_request/url_request.cc',
         'url_request/url_request.h',
         'url_request/url_request_about_job.cc',
         'url_request/url_request_about_job.h',
         'url_request/url_request_context.cc',
         'url_request/url_request_context.h',
         'url_request/url_request_data_job.cc',
         'url_request/url_request_data_job.h',
         'url_request/url_request_error_job.cc',
         'url_request/url_request_error_job.h',
@@ skipping 290 matching lines @@
         'spdy/spdy_stream_unittest.cc',
         'spdy/spdy_test_util.cc',
         'spdy/spdy_test_util.h',
         'test/python_utils_unittest.cc',
         'tools/dump_cache/url_to_filename_encoder.cc',
         'tools/dump_cache/url_to_filename_encoder.h',
         'tools/dump_cache/url_to_filename_encoder_unittest.cc',
         'tools/dump_cache/url_utilities.h',
         'tools/dump_cache/url_utilities.cc',
         'tools/dump_cache/url_utilities_unittest.cc',
+        'url_request/request_throttler_unittest.cc',
         'url_request/url_request_job_tracker_unittest.cc',
         'url_request/url_request_unittest.cc',
         'url_request/url_request_unittest.h',
         'url_request/view_cache_helper_unittest.cc',
         'websockets/websocket_frame_handler_unittest.cc',
         'websockets/websocket_handshake_draft75_unittest.cc',
         'websockets/websocket_handshake_handler_unittest.cc',
         'websockets/websocket_handshake_unittest.cc',
         'websockets/websocket_job_unittest.cc',
         'websockets/websocket_net_log_params_unittest.cc',
@@ skipping 467 matching lines @@
       ],
     }],
   ],
 }
 
 # Local Variables:
 # tab-width:2
 # indent-tabs-mode:nil
 # End:
 # vim: set expandtab tabstop=2 shiftwidth=2: