Android: Annotate and generate JNI code for VideoFrame.java

This CL also merged native_handle_impl.cc and videoframe_jni.cc to keep
all JNI code for the same Java class in the same file, and also renames
this file to jni/videoframe.cc.

The classes AndroidVideoBufferFactory and JavaVideoFrameFactory are
now unnecessary since we cache everything and can be simplified to
global static functions instead.

Bug: webrtc:8278
Change-Id: I03d7b0bbde64cfb407cd6210478ddf9d5599cd8c
Reviewed-on: https://webrtc-review.googlesource.com/22923
Commit-Queue: Magnus Jedvert <magjed@webrtc.org>
Reviewed-by: Sami Kalliomäki <sakal@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20677}
diff --git a/sdk/android/src/jni/videodecoderwrapper.h b/sdk/android/src/jni/videodecoderwrapper.h
index 978be87..f56b49e 100644
--- a/sdk/android/src/jni/videodecoderwrapper.h
+++ b/sdk/android/src/jni/videodecoderwrapper.h
@@ -17,7 +17,7 @@
 #include "api/video_codecs/video_decoder.h"
 #include "common_video/h264/h264_bitstream_parser.h"
 #include "sdk/android/src/jni/jni_helpers.h"
-#include "sdk/android/src/jni/native_handle_impl.h"
+#include "sdk/android/src/jni/videoframe.h"
 
 namespace webrtc {
 namespace jni {
@@ -78,7 +78,6 @@
   int32_t number_of_cores_;
 
   bool initialized_;
-  AndroidVideoBufferFactory android_video_buffer_factory_;
   std::deque<FrameExtraInfo> frame_extra_infos_;
   bool qp_parsing_enabled_;
   H264BitstreamParser h264_bitstream_parser_;