Rework use counter for navigator.share to use [MeasureAs].

Use automatic functionality instead of manually calling
UseCounter::count.

BUG=636288

Review-Url: https://codereview.chromium.org/2250613002
Cr-Commit-Position: refs/heads/master@{#417228}

third_party/WebKit/Source/modules/webshare/NavigatorShare.cpp

@@ -9,7 +9,6 @@
 #include "core/dom/ExceptionCode.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Navigator.h"
-#include "core/frame/UseCounter.h"
 #include "modules/webshare/ShareData.h"
 #include "platform/UserGestureIndicator.h"
 #include "platform/mojo/MojoHelper.h"
@@ -83,16 +82,14 @@ const char* NavigatorShare::supplementName()
 
 ScriptPromise NavigatorShare::share(ScriptState* scriptState, const ShareData& shareData)
 {
-    Document* doc = toDocument(scriptState->getExecutionContext());
-    DCHECK(doc);
-    UseCounter::count(*doc, UseCounter::WebShareShare);
-
     if (!UserGestureIndicator::utilizeUserGesture()) {
         DOMException* error = DOMException::create(SecurityError, "Must be handling a user gesture to perform a share request.");
         return ScriptPromise::rejectWithDOMException(scriptState, error);
     }
 
     if (!m_service) {
+        Document* doc = toDocument(scriptState->getExecutionContext());
+        DCHECK(doc);
         LocalFrame* frame = doc->frame();
         DCHECK(frame);
         frame->interfaceProvider()->getInterface(mojo::GetProxy(&m_service));

third_party/WebKit/Source/modules/webshare/NavigatorShare.idl

@@ -7,5 +7,6 @@
 [
   OriginTrialEnabled=WebShare,
 ] partial interface Navigator {
-  [CallWith=ScriptState] Promise<void> share(ShareData data);
+  [CallWith=ScriptState, MeasureAs=WebShareShare]
+  Promise<void> share(ShareData data);
 };