Implement H.264 packetization mode 0.

This approach extends the H.264 specific information with
a packetization mode enum.

Status: Parameter is in code. No way to set it yet.

Rebase of CL  2009213002

BUG=600254

Review-Url: https://codereview.webrtc.org/2337453002
Cr-Commit-Position: refs/heads/master@{#15032}

webrtc/api/android/jni/androidmediaencoder_jni.cc

@@ -1113,6 +1113,9 @@ bool MediaCodecVideoEncoder::DeliverPendingOutputs(JNIEnv* jni) {
           info.codecSpecific.VP9.height[0] = height_;
           info.codecSpecific.VP9.gof.CopyGofInfoVP9(gof_);
         }
+      } else if (codecType_ == kVideoCodecH264) {
+        info.codecSpecific.H264.packetization_mode =
+            webrtc::kH264PacketizationMode1;
       }
       picture_id_ = (picture_id_ + 1) & 0x7FFF;