ShapeDetection: Holding all of mock service to prevent GC

third_party/WebKit/LayoutTests/shapedetection/resources/mock-facedetection.js

Index: third_party/WebKit/LayoutTests/shapedetection/resources/mock-facedetection.js
diff --git a/third_party/WebKit/LayoutTests/shapedetection/resources/mock-facedetection.js b/third_party/WebKit/LayoutTests/shapedetection/resources/mock-facedetection.js
index 1faf89f7727c4a8bcbeb293978e3c643e5d2693a..d1d1f590695d7b21f852bac13dfe8a6c7efc5f9a 100644
--- a/third_party/WebKit/LayoutTests/shapedetection/resources/mock-facedetection.js
+++ b/third_party/WebKit/LayoutTests/shapedetection/resources/mock-facedetection.js
@@ -17,22 +17,25 @@ let mockFaceDetectionProviderReady = define(
       interfaces.addInterfaceOverrideForTesting(
           faceDetectionProvider.FaceDetectionProvider.name,
           handle => this.bindingSet_.addBinding(this, handle));
+
+      this.mockServiceInstances_ = [];
     }
 
     createFaceDetection(request, options) {
-      this.mock_service_ = new MockFaceDetection(request, options);
+      this.mockServiceInstances_.push(new MockFaceDetection(request, options));
+      this.index = this.mockServiceInstances_.length -1;

[Ken Rockot(use gerrit already), 2017/05/17 15:29:23]

You established in your previous reply that multiple tests may run concurrently
in the same context. That would make this code incorrect. i.e. it's possible for
the following sequence of events to occur:

 test1: createFaceDetection()  // index gets set to 0
 test2: createFaceDetection()  // index gets set to 1
 test1: call getFrameData()    // returns instance[1].bufferData_ instead of
instance[0].bufferData_

     }
 
     getFrameData() {
-      return this.mock_service_.buffer_data_;
+      return this.mockServiceInstances_[this.index].bufferData_;
     }
 
     getMaxDetectedFaces() {
-     return this.mock_service_.maxDetectedFaces_;
+     return this.mockServiceInstances_[this.index].maxDetectedFaces_;
     }
 
     getFastMode () {
-      return this.mock_service_.fastMode_;
+      return this.mockServiceInstances_[this.index].fastMode_;
     }
   }
 
@@ -46,7 +49,7 @@ let mockFaceDetectionProviderReady = define(
 
     detect(frame_data, width, height) {
       let receivedStruct = mojo.mapBuffer(frame_data, 0, width*height*4, 0);
-      this.buffer_data_ = new Uint32Array(receivedStruct.buffer);
+      this.bufferData_ = new Uint32Array(receivedStruct.buffer);
       return Promise.resolve({
         result: {
           bounding_boxes: [