Video capture Android: enable unittests for Camera2 API

media/capture/video/android/java/src/org/chromium/media/VideoCapture.java

Index: media/capture/video/android/java/src/org/chromium/media/VideoCapture.java
diff --git a/media/capture/video/android/java/src/org/chromium/media/VideoCapture.java b/media/capture/video/android/java/src/org/chromium/media/VideoCapture.java
index 42931f333bb4ca9f8eb7436b9adac71ad50ac356..4e0aff02fe021ae8989d97f386539e1a1da27173 100644
--- a/media/capture/video/android/java/src/org/chromium/media/VideoCapture.java
+++ b/media/capture/video/android/java/src/org/chromium/media/VideoCapture.java
@@ -34,6 +34,8 @@ public abstract class VideoCapture {
     // Native callback context variable.
     protected final long mNativeVideoCaptureDeviceAndroid;
 
+    protected boolean mUseBackgroundThreadForTesting = false;
+
     VideoCapture(Context context, int id, long nativeVideoCaptureDeviceAndroid) {
         mContext = context;
         mId = id;
@@ -109,6 +111,11 @@ public abstract class VideoCapture {
         }
     }
 
+    @CalledByNative
+    public final void setTestMode() {
+        mUseBackgroundThreadForTesting = true;
+    }
+
     protected final int getCameraRotation() {
         int rotation = mInvertDeviceOrientationReadings ? (360 - getDeviceRotation())
                                                         : getDeviceRotation();