Shape Detection: use Google Play services Face detection where available

services/shape_detection/android/java/src/org/chromium/shape_detection/FaceDetectionImpl.java

Index: services/shape_detection/android/java/src/org/chromium/shape_detection/FaceDetectionImpl.java
diff --git a/services/shape_detection/android/java/src/org/chromium/shape_detection/FaceDetectionImpl.java b/services/shape_detection/android/java/src/org/chromium/shape_detection/FaceDetectionImpl.java
index 0d7dcbb9f6c3671158b86139e509c93ff7b0c486..4d88df132ea630035c9358cb2dcdfaf8b07fd996 100644
--- a/services/shape_detection/android/java/src/org/chromium/shape_detection/FaceDetectionImpl.java
+++ b/services/shape_detection/android/java/src/org/chromium/shape_detection/FaceDetectionImpl.java
@@ -18,6 +18,7 @@ import org.chromium.mojo.system.SharedBufferHandle.MapFlags;
 import org.chromium.shape_detection.mojom.FaceDetection;
 import org.chromium.shape_detection.mojom.FaceDetectionResult;
 import org.chromium.shape_detection.mojom.FaceDetectorOptions;
+import org.chromium.shape_detection.mojom.Landmark;
 
 import java.nio.ByteBuffer;
 
@@ -104,6 +105,8 @@ public class FaceDetectionImpl implements FaceDetection {
                     faceArray[i].boundingBox.width = 2 * eyesDistance;
                     faceArray[i].boundingBox.height = 2 * eyesDistance;
                     // TODO(xianglu): Consider adding Face.confidence and Face.pose.
+
+                    faceArray[i].landmarks = new Landmark[0];

[Reilly Grant (use Gerrit), 2017/05/11 18:45:22]

Why did this become necessary?

[mcasas, 2017/05/11 18:51:22]

I believe leaving it empty caused a problem when
deserializing: |landmarks| is an array of mojo Structs.

[mcasas, 2017/05/11 19:00:58]

Correction: it fails in the serialization:

                 }
 
                 callback.call(faceArray);