Added audioSessionDidActivate and audioSessionDidDectivate

webrtc/modules/audio_device/ios/objc/RTCAudioSessionTest.mm

Index: webrtc/modules/audio_device/ios/objc/RTCAudioSessionTest.mm
diff --git a/webrtc/modules/audio_device/ios/objc/RTCAudioSessionTest.mm b/webrtc/modules/audio_device/ios/objc/RTCAudioSessionTest.mm
index cb87910feed9add9ae0e8b2131b67715f91b15bf..3f55077ed213a1ac6aed75e6befb2def545d7c49 100644
--- a/webrtc/modules/audio_device/ios/objc/RTCAudioSessionTest.mm
+++ b/webrtc/modules/audio_device/ios/objc/RTCAudioSessionTest.mm
@@ -176,6 +176,15 @@
   EXPECT_EQ(0u, session.delegates.size());
 }
 
+- (void)testAudioSessionActivation {
+  RTCAudioSession *audioSession = [RTCAudioSession sharedInstance];
+  EXPECT_EQ(0, audioSession.activationCount);
+  [audioSession audioSessionDidActivate:[AVAudioSession sharedInstance]];
+  EXPECT_EQ(1, audioSession.activationCount);
+  [audioSession audioSessionDidDeactivate:[AVAudioSession sharedInstance]];
+  EXPECT_EQ(0, audioSession.activationCount);
+}
+
 @end
 
 namespace webrtc {
@@ -215,4 +224,10 @@ TEST_F(AudioSessionTest, RemoveDelegateOnDealloc) {
   [test testRemoveDelegateOnDealloc];
 }
 
+TEST_F(AudioSessionTest, AudioSessionActivation) {
+  RTCAudioSessionTest *test = [[RTCAudioSessionTest alloc] init];
+  [test testAudioSessionActivation];
+}
+
+
 }  // namespace webrtc