Modify bitrate controller to update bitrate based on process call and not
only whenever a RTCP receiver block is received.

Additionally:
 Add condition to only start rampup after a receiver block is received. This was same as old behaviour but now an explicit check is needed to verify process does not ramps up before the first block.

 Fix logic around capping max bitrate increase at 8% per second. Before it was only increasing once every 1 second and each increase would be as high as 8%. If receiver blocks had a different interval before it would lose an update or waste an update slot and not ramp up as much as a 8% (e.g. if RTCP received < 1 second).

 Did not touch decrease logic, however since it can be triggered more often it
 may decrease much faster and closer to the original written cap of once every
 300ms + rtt.

Note:
 rampup_tests.cc don't seem to be affected by this since there is no packet loss or REMB that go higher than expected cap.
 bitrate_controller_unittests.cc are don't really simulate a clock and the process thread, but trigger update by inserting an rtcp block.

BUG=3065
R=stefan@webrtc.org, mflodman@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/10529004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5775 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/modules/bitrate_controller/include/bitrate_controller.h b/webrtc/modules/bitrate_controller/include/bitrate_controller.h
index 0f74367..1d90cb9 100644
--- a/webrtc/modules/bitrate_controller/include/bitrate_controller.h
+++ b/webrtc/modules/bitrate_controller/include/bitrate_controller.h
@@ -15,6 +15,7 @@
 #ifndef WEBRTC_MODULES_BITRATE_CONTROLLER_INCLUDE_BITRATE_CONTROLLER_H_
 #define WEBRTC_MODULES_BITRATE_CONTROLLER_INCLUDE_BITRATE_CONTROLLER_H_
 
+#include "webrtc/modules/interface/module.h"
 #include "webrtc/modules/rtp_rtcp/interface/rtp_rtcp_defines.h"
 
 namespace webrtc {
@@ -35,7 +36,7 @@
   virtual ~BitrateObserver() {}
 };
 
-class BitrateController {
+class BitrateController : public Module {
 /*
  * This class collects feedback from all streams sent to a peer (via
  * RTCPBandwidthObservers). It does one  aggregated send side bandwidth
@@ -48,7 +49,8 @@
   // When true, the bitrate will never be set lower than the minimum bitrate(s).
   // When false, the bitrate observers will be allocated rates up to their
   // respective minimum bitrate, satisfying one observer after the other.
-  static BitrateController* CreateBitrateController(bool enforce_min_bitrate);
+  static BitrateController* CreateBitrateController(Clock* clock,
+                                                    bool enforce_min_bitrate);
   virtual ~BitrateController() {}
 
   virtual RtcpBandwidthObserver* CreateRtcpBandwidthObserver() = 0;