Instrument ScreenOrientation.[angle|type] for identifiability study.

Bug: 973801
Change-Id: I37abe1065f80f4c2d7aca88f09dfd0ebb85cfa8c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2352512Reviewed-by: Asanka Herath <asanka@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Commit-Queue: Dylan Cutler <dylancutler@google.com>
Cr-Commit-Position: refs/heads/master@{#799735}

third_party/blink/renderer/modules/screen_orientation/screen_orientation.idl

@@ -24,8 +24,8 @@ enum OrientationType {
 
 [Exposed=Window]
 interface ScreenOrientation : EventTarget {
-    [MeasureAs=ScreenOrientationAngle] readonly attribute unsigned short angle;
-    [MeasureAs=ScreenOrientationType] readonly attribute DOMString type;
+    [HighEntropy=Direct, MeasureAs=ScreenOrientationAngle] readonly attribute unsigned short angle;
+    [HighEntropy=Direct, MeasureAs=ScreenOrientationType] readonly attribute DOMString type;
 
     [CallWith=ScriptState, MeasureAs=ScreenOrientationLock, RaisesException] Promise<void> lock(OrientationLockType orientation);
     [MeasureAs=ScreenOrientationUnlock] void unlock();