Fix receiving H264 video from iPhone on Kitkat devices.

Changing this constant has been empirically proven to solve the issue.

BUG=webrtc:6455,b/31827852

Review-Url: https://codereview.webrtc.org/2382733006
Cr-Commit-Position: refs/heads/master@{#14479}
diff --git a/webrtc/api/android/jni/androidmediacodeccommon.h b/webrtc/api/android/jni/androidmediacodeccommon.h
index 528e166..a7c5eaa 100644
--- a/webrtc/api/android/jni/androidmediacodeccommon.h
+++ b/webrtc/api/android/jni/androidmediacodeccommon.h
@@ -59,7 +59,7 @@
 // Maximum amount of pending frames for VP9 decoder.
 enum { kMaxPendingFramesVp9 = 1 };
 // Maximum amount of pending frames for H.264 decoder.
-enum { kMaxPendingFramesH264 = 3 };
+enum { kMaxPendingFramesH264 = 4 };
 // Maximum amount of decoded frames for which per-frame logging is enabled.
 enum { kMaxDecodedLogFrames = 10 };
 // Maximum amount of encoded frames for which per-frame logging is enabled.