BWE allocation strategy allows controlling of bitrate allocation with WEBRTC external logic.

This CL implements the main logic and IOS appRTC integration.

Unit tests and Android appRTC will be in separate CL.

Bug: webrtc:8243
Change-Id: If8e5195294046a47316e9fade1b0dfec211155e1
Reviewed-on: https://webrtc-review.googlesource.com/4860
Commit-Queue: Alex Narest <alexnarest@webrtc.org>
Reviewed-by: Niels Moller <nisse@webrtc.org>
Reviewed-by: Stefan Holmer <stefan@webrtc.org>
Reviewed-by: Taylor Brandstetter <deadbeef@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20329}
diff --git a/sdk/objc/Framework/Headers/WebRTC/RTCPeerConnection.h b/sdk/objc/Framework/Headers/WebRTC/RTCPeerConnection.h
index 7b0c449..c74af13 100644
--- a/sdk/objc/Framework/Headers/WebRTC/RTCPeerConnection.h
+++ b/sdk/objc/Framework/Headers/WebRTC/RTCPeerConnection.h
@@ -24,6 +24,7 @@
 @class RTCRtpSender;
 @class RTCSessionDescription;
 @class RTCLegacyStatsReport;
+@class RTCBitrateAllocationStrategy;
 
 NS_ASSUME_NONNULL_BEGIN
 
@@ -193,6 +194,13 @@
           currentBitrateBps:(nullable NSNumber *)currentBitrateBps
               maxBitrateBps:(nullable NSNumber *)maxBitrateBps;
 
+/** Sets current strategy. If not set default WebRTC allocator will be used.
+ *   May be changed during an active session. The strategy
+ *   ownership is passed with std::unique_ptr
+ */
+- (void)setBitrateAllocationStrategy:
+        (RTCBitrateAllocationStrategy *_Nullable)bitrateAllocationStrategy;
+
 /** Start or stop recording an Rtc EventLog. */
 - (BOOL)startRtcEventLogWithFilePath:(NSString *)filePath
                       maxSizeInBytes:(int64_t)maxSizeInBytes;