Shape Detection: use constructors for UMA counters instead of detect() methods

Remove the per-detect() UMA counters and use instead constructors,
because in a normal usage pattern the detect() method can be called
many times on the same object, and we don't want to skew the UMA.

Bug: 659138
Change-Id: Ib4aef88c35dd4853ececbf71cc12a96eaca020f3
Reviewed-on: https://chromium-review.googlesource.com/511344
Commit-Queue: Miguel Casas <mcasas@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#473798}

third_party/WebKit/Source/core/frame/UseCounter.h

@@ -1310,8 +1310,6 @@ class CORE_EXPORT UseCounter {
 
     kCSSFlexibleBox = 1692,
     kCSSGridLayout = 1693,
-    kV8BarcodeDetector_Detect_Method = 1694,
-    kV8FaceDetector_Detect_Method = 1695,
     kFullscreenAllowedByOrientationChange = 1696,
     kServiceWorkerRespondToNavigationRequestWithRedirectedResponse = 1697,
     kV8AudioContext_Constructor = 1698,
@@ -1413,7 +1411,6 @@ class CORE_EXPORT UseCounter {
     kCSSValueUserModifyReadOnly = 1798,
     kCSSValueUserModifyReadWrite = 1799,
     kCSSValueUserModifyReadWritePlaintextOnly = 1800,
-    kV8TextDetector_Detect_Method = 1801,
     kCSSValueOnDemand = 1802,
     kServiceWorkerNavigationPreload = 1803,
     kFullscreenRequestWithPendingElement = 1804,
@@ -1602,6 +1599,9 @@ class CORE_EXPORT UseCounter {
     kCredentialManagerCustomFetch = 1988,
     kNetInfoRtt = 1989,
     kNetInfoDownlink = 1990,
+    kShapeDetection_BarcodeDetectorConstructor = 1991,
+    kShapeDetection_FaceDetectorConstructor = 1992,
+    kShapeDetection_TextDetectorConstructor = 1993,
 
     // Add new features immediately above this line. Don't change assigned
     // numbers of any item, and don't reuse removed slots.

third_party/WebKit/Source/modules/shapedetection/BarcodeDetector.idl

@@ -7,7 +7,8 @@
 [
     Constructor,
     Exposed=(Window,Worker),
+    MeasureAs=ShapeDetection_BarcodeDetectorConstructor,
     RuntimeEnabled=ShapeDetection,
 ] interface BarcodeDetector {
-    [CallWith=ScriptState, Measure] Promise<sequence<DetectedBarcode>> detect(ImageBitmapSource image);
+    [CallWith=ScriptState] Promise<sequence<DetectedBarcode>> detect(ImageBitmapSource image);
 };

third_party/WebKit/Source/modules/shapedetection/FaceDetector.idl

@@ -7,7 +7,8 @@
 [
     Constructor(optional FaceDetectorOptions faceDetectorOptions),
     Exposed=(Window,Worker),
+    MeasureAs=ShapeDetection_FaceDetectorConstructor,
     RuntimeEnabled=ShapeDetection,
 ] interface FaceDetector {
-    [CallWith=ScriptState, Measure] Promise<sequence<DetectedFace>> detect(ImageBitmapSource image);
+    [CallWith=ScriptState] Promise<sequence<DetectedFace>> detect(ImageBitmapSource image);
 };

third_party/WebKit/Source/modules/shapedetection/TextDetector.idl

@@ -7,7 +7,8 @@
 [
     Constructor,
     Exposed=(Window,Worker),
+    MeasureAs=ShapeDetection_TextDetectorConstructor,
     RuntimeEnabled=ShapeDetection,
 ] interface TextDetector {
-    [CallWith=ScriptState, Measure] Promise<sequence<DetectedText>> detect(ImageBitmapSource image);
+    [CallWith=ScriptState] Promise<sequence<DetectedText>> detect(ImageBitmapSource image);
 };

tools/metrics/histograms/enums.xml

@@ -15005,6 +15005,9 @@ uploading your change for review.  These are checked by presubmit scripts.
   <int value="1988" label="CredentialManagerCustomFetch"/>
   <int value="1989" label="NetInfoRtt"/>
   <int value="1990" label="NetInfoDownlink"/>
+  <int value="1991" label="ShapeDetection_BarcodeDetectorConstructor"/>
+  <int value="1992" label="ShapeDetection_FaceDetectorConstructor"/>
+  <int value="1993" label="ShapeDetection_TextDetectorConstructor"/>
 </enum>
 
 <enum name="FeedbackSource" type="int">