Shape Detection: Implement FaceDetection on Mac as out-of-process service

third_party/WebKit/Source/modules/shapedetection/ShapeDetector.cpp

Index: third_party/WebKit/Source/modules/shapedetection/ShapeDetector.cpp
diff --git a/third_party/WebKit/Source/modules/shapedetection/ShapeDetector.cpp b/third_party/WebKit/Source/modules/shapedetection/ShapeDetector.cpp
index abfa2e3ddf937b308d08632890be87dd3294b2fc..a94c8a52eee4549d7b304ad1eb5101431910bb49 100644
--- a/third_party/WebKit/Source/modules/shapedetection/ShapeDetector.cpp
+++ b/third_party/WebKit/Source/modules/shapedetection/ShapeDetector.cpp
@@ -15,8 +15,10 @@
 #include "core/html/HTMLVideoElement.h"
 #include "core/html/canvas/CanvasImageSource.h"
 #include "modules/shapedetection/DetectedBarcode.h"
+#include "platform/ServiceConnector.h"
 #include "platform/graphics/Image.h"
 #include "public/platform/InterfaceProvider.h"
+#include "services/shape_detection/public/interfaces/constants.mojom-blink.h"
 #include "third_party/skia/include/core/SkImage.h"
 #include "third_party/skia/include/core/SkImageInfo.h"
 #include "wtf/CheckedNumeric.h"
@@ -43,12 +45,23 @@ static CanvasImageSource* toImageSourceInternal(
 
 }  // anonymous namespace
 
+// TODO(xianglu): We don't need a service per frame. Remove this argument.
 ShapeDetector::ShapeDetector(LocalFrame& frame) {
   DCHECK(!m_faceService.is_bound());
   DCHECK(!m_barcodeService.is_bound());
+#if OS(MACOSX)
+  ServiceConnector::instance().ConnectToInterface(

[yzshen1, 2016/12/01 21:28:26]

Do we always need both m_faceService and m_barcodeService? could they be
initilalized when needed?

[xianglu, 2016/12/02 18:11:24]

That's a good point. I separated them to two constructors.

[yzshen1, 2016/12/05 17:41:19]

Depending on which constructor is called, this instance can only serve one type
of detection task (either barcode or face). In that case, it is redundant to
have |detectorType| parameter in the detectShapes() function signature. Right?

It seems to me you could either (1) eliminate |detectorType|, or (2) still use a
single constructor and lazily initialize |m_barcodeService| / |m_barcodeService|
when needed.

[xianglu, 2016/12/05 18:50:02]

Yes. ShapeDetector only serves one task, and users call either FaceDetector() or
BarcodeDetector(). Removing detectorType would be a good solution. However, it
might involve quite a bit of code refactoring. I think it's better to include
that in a separate CL.

+      shape_detection::mojom::blink::kServiceName,
+      mojo::GetProxy(&m_faceService));
+  ServiceConnector::instance().ConnectToInterface(
+      shape_detection::mojom::blink::kServiceName,
+      mojo::GetProxy(&m_barcodeService));
+#else
+  // TODO(xianglu): Move Android implementation to service/ as well.
   DCHECK(frame.interfaceProvider());
   frame.interfaceProvider()->getInterface(mojo::GetProxy(&m_faceService));
   frame.interfaceProvider()->getInterface(mojo::GetProxy(&m_barcodeService));
+#endif
   m_faceService.set_connection_error_handler(convertToBaseCallback(WTF::bind(
       &ShapeDetector::onFaceServiceConnectionError, wrapWeakPersistent(this))));
   m_barcodeService.set_connection_error_handler(convertToBaseCallback(