Reland: Video capture Android: enable unittests for Camera2 API

media/capture/video/android/java/src/org/chromium/media/VideoCaptureCamera2.java

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.media;
 
 import android.annotation.TargetApi;
 import android.content.Context;
 import android.graphics.ImageFormat;
 import android.graphics.Rect;
@@ skipping 225 matching lines @@
     private static final double kNanoSecondsToFps = 1.0E-9;
     private static final String TAG = "VideoCapture";
 
     private static enum CameraState { OPENING, CONFIGURING, STARTED, STOPPED }
 
     private final Object mCameraStateLock = new Object();
 
     private CameraDevice mCameraDevice;
     private CameraCaptureSession mPreviewSession;
     private CaptureRequest mPreviewRequest;
+    private Handler mMainHandler = null;
 
     private CameraState mCameraState = CameraState.STOPPED;
     private final float mMaxZoom;
     private Rect mCropRect = new Rect();
     private int mPhotoWidth = 0;
     private int mPhotoHeight = 0;
     private int mFocusMode = AndroidMeteringMode.CONTINUOUS;
     private int mExposureMode = AndroidMeteringMode.CONTINUOUS;
     private MeteringRectangle mAreaOfInterest;
     private int mExposureCompensation = 0;
@@ skipping 193 matching lines @@
                 && cameraCharacteristics.get(CameraCharacteristics.INFO_SUPPORTED_HARDWARE_LEVEL)
                 == CameraMetadata.INFO_SUPPORTED_HARDWARE_LEVEL_LEGACY;
     }
 
     static int getNumberOfCameras(Context appContext) {
         final CameraManager manager =
                 (CameraManager) appContext.getSystemService(Context.CAMERA_SERVICE);
         try {
             return manager.getCameraIdList().length;
         } catch (CameraAccessException | SecurityException ex) {
-            // SecurityException is an undocumented exception, but has been seen in
-            // http://crbug/605424.
+            // SecurityException is undocumented but seen in the wild: https://crbug/605424.
             Log.e(TAG, "getNumberOfCameras: getCameraIdList(): ", ex);
             return 0;
         }
     }
 
     static int getCaptureApiType(int id, Context appContext) {
         final CameraCharacteristics cameraCharacteristics =
                 getCameraCharacteristics(appContext, id);
         if (cameraCharacteristics == null) {
             return VideoCaptureApi.UNKNOWN;
@@ skipping 107 matching lines @@
                 == CameraCharacteristics.LENS_FACING_BACK;
         return true;
     }
 
     @Override
     public boolean startCapture() {
         Log.d(TAG, "startCapture");
         changeCameraStateAndNotify(CameraState.OPENING);
         final CameraManager manager =
                 (CameraManager) mContext.getSystemService(Context.CAMERA_SERVICE);
-        final Handler mainHandler = new Handler(mContext.getMainLooper());
+
+        if (!mUseBackgroundThreadForTesting) {
+            mMainHandler = new Handler(mContext.getMainLooper());
+        } else {
+            // Usually we deliver frames on |mContext|s thread, but unit tests
+            // occupy its Looper; deliver frames on a background thread instead.
+            HandlerThread thread = new HandlerThread("CameraPicture");
+            thread.start();
+            mMainHandler = new Handler(thread.getLooper());
+        }
+
         final CrStateListener stateListener = new CrStateListener();
         try {
-            manager.openCamera(Integer.toString(mId), stateListener, mainHandler);
+            manager.openCamera(Integer.toString(mId), stateListener, mMainHandler);
         } catch (CameraAccessException | IllegalArgumentException | SecurityException ex) {
             Log.e(TAG, "allocate: manager.openCamera: ", ex);
             return false;
         }
 
         return true;
     }
 
     @Override
     public boolean stopCapture() {
@@ skipping 14 matching lines @@
         }
 
         try {
             mPreviewSession.abortCaptures();
         } catch (CameraAccessException | IllegalStateException ex) {
             Log.e(TAG, "abortCaptures: ", ex);
             return false;
         }
         if (mCameraDevice == null) return false;
         mCameraDevice.close();
+
+        if (mUseBackgroundThreadForTesting) mMainHandler.getLooper().quit();
+
         changeCameraStateAndNotify(CameraState.STOPPED);
         mCropRect = new Rect();
         return true;
     }
 
     public PhotoCapabilities getPhotoCapabilities() {
         final CameraCharacteristics cameraCharacteristics = getCameraCharacteristics(mContext, mId);
         PhotoCapabilities.Builder builder = new PhotoCapabilities.Builder();
 
         int minIso = 0;
@@ skipping 254 matching lines @@
             return false;
         }
         return true;
     }
 
     @Override
     public void deallocate() {
         Log.d(TAG, "deallocate");
     }
 }