Move congestion controller to a separate module.

webrtc/modules/congestion_controller/BUILD.gn

 # Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
 #
 # Use of this source code is governed by a BSD-style license
 # that can be found in the LICENSE file in the root of the source
 # tree. An additional intellectual property rights grant can be found
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
 import("../../build/webrtc.gni")
 
-source_set("bitrate_controller") {
+source_set("congestion_controller") {
   sources = [
-    "bitrate_controller_impl.cc",
-    "bitrate_controller_impl.h",
-    "include/bitrate_allocator.h",
-    "include/bitrate_controller.h",
-    "send_side_bandwidth_estimation.cc",
-    "send_side_bandwidth_estimation.h",
+    "congestion_controller.cc",
+    "include/congestion_controller.h",
   ]
 
   if (is_win) {
     cflags = [
       # TODO(jschuh): Bug 1348: fix this warning.
       "/wd4267",  # size_t to int truncations
     ]
   }
 
   configs += [ "../..:common_config" ]
   public_configs = [ "../..:common_inherited_config" ]
 
   if (is_clang) {
     # Suppress warnings from Chrome's Clang plugins.
     # See http://code.google.com/p/webrtc/issues/detail?id=163 for details.
     configs -= [ "//build/config/clang:find_bad_constructs" ]
   }
 
   deps = [
-    "../../system_wrappers",
+    "../bitrate_controller",
+    "../pacing",
+    "../remote_bitrate_estimator",
   ]
 }