Optimize HardwareVideoDecoder by doing all frame conversions in C++.

webrtc/sdk/android/BUILD.gn

Index: webrtc/sdk/android/BUILD.gn
diff --git a/webrtc/sdk/android/BUILD.gn b/webrtc/sdk/android/BUILD.gn
index c13f426dbde2b169af5f7976d88c613ce69e9cff..48ed324a2d7fddbcfdad1cb8dd7eefed666bf7a3 100644
--- a/webrtc/sdk/android/BUILD.gn
+++ b/webrtc/sdk/android/BUILD.gn
@@ -97,6 +97,7 @@ rtc_static_library("video_jni") {
     "src/jni/filevideocapturer_jni.cc",
     "src/jni/native_handle_impl.cc",
     "src/jni/native_handle_impl.h",
+    "src/jni/nv12buffer_jni.cc",
     "src/jni/pc/video_jni.cc",
     "src/jni/surfacetexturehelper_jni.cc",
     "src/jni/surfacetexturehelper_jni.h",
@@ -436,6 +437,7 @@ android_library("libjingle_peerconnection_java") {
     "src/java/org/webrtc/Histogram.java",
     "src/java/org/webrtc/I420BufferImpl.java",
     "src/java/org/webrtc/MediaCodecUtils.java",
+    "src/java/org/webrtc/NV12Buffer.java",
     "src/java/org/webrtc/TextureBufferImpl.java",
     "src/java/org/webrtc/VideoCodecType.java",
     "src/java/org/webrtc/VideoDecoderWrapperCallback.java",