Support for video file instead of camera and output video out to file

webrtc/api/BUILD.gn

Index: webrtc/api/BUILD.gn
diff --git a/webrtc/api/BUILD.gn b/webrtc/api/BUILD.gn
index bd701790b288c0b7c69fb97a525deee5417bc0ff..9aab184d91f63d9db5ef318ea52d8647b5f5c82c 100644
--- a/webrtc/api/BUILD.gn
+++ b/webrtc/api/BUILD.gn
@@ -262,6 +262,7 @@ if (is_android && !build_with_chromium) {
       "android/java/src/org/webrtc/EglBase10.java",
       "android/java/src/org/webrtc/EglBase14.java",
       "android/java/src/org/webrtc/EglRenderer.java",
+      "android/java/src/org/webrtc/FileVideoCapturer.java",
       "android/java/src/org/webrtc/GlRectDrawer.java",
       "android/java/src/org/webrtc/GlShader.java",
       "android/java/src/org/webrtc/GlTextureFrameBuffer.java",
@@ -290,6 +291,7 @@ if (is_android && !build_with_chromium) {
       "android/java/src/org/webrtc/SurfaceViewRenderer.java",
       "android/java/src/org/webrtc/VideoCapturer.java",
       "android/java/src/org/webrtc/VideoCapturerAndroid.java",
+      "android/java/src/org/webrtc/VideoFileRenderer.java",
       "android/java/src/org/webrtc/VideoRenderer.java",
       "android/java/src/org/webrtc/VideoRendererGui.java",
       "android/java/src/org/webrtc/VideoSource.java",