Support UseCounter in dedicated workers.

Source/core/frame/UseCounter.h

Index: Source/core/frame/UseCounter.h
diff --git a/Source/core/frame/UseCounter.h b/Source/core/frame/UseCounter.h
index 8d0abe4a6564e2beb0a70bb82bb8cdeffddac986..80d3bfb9d28984a18739d8236b429823f51cd531 100644
--- a/Source/core/frame/UseCounter.h
+++ b/Source/core/frame/UseCounter.h
@@ -278,7 +278,7 @@ public:
         HTMLMediaElementSeekToFragmentStart = 281,
         HTMLMediaElementPauseAtFragmentEnd = 282,
         PrefixedWindowURL = 283,
-        PrefixedWorkerURL = 284,
+        PrefixedWorkerURL = 284, // This didn't work because of crbug.com/376039. Available since M37.
         WindowOrientation = 285,
         DOMStringListContains = 286,
         DocumentCaptureEvents = 287,
@@ -307,8 +307,8 @@ public:
         NamedNodeMapGetNamedItemNS = 310,
         NamedNodeMapSetNamedItemNS = 311,
         NamedNodeMapRemoveNamedItemNS = 312,
-        OpenWebDatabaseInWorker = 313, // This doesn't work because of crbug.com/376039.
-        OpenWebDatabaseSyncInWorker = 314, // This doesn't work because of crbug.com/376039.
+        OpenWebDatabaseInWorker = 313, // This didn't work because of crbug.com/376039. Available since M37.
+        OpenWebDatabaseSyncInWorker = 314, // This didn't work because of crbug.com/376039. Available since M37.
         PrefixedAllowFullscreenAttribute = 315,
         XHRProgressEventPosition = 316,
         XHRProgressEventTotalSize = 317,
@@ -478,7 +478,8 @@ public:
 
     // "count" sets the bit for this feature to 1. Repeated calls are ignored.
     static void count(const Document&, Feature);
-    // This doesn't count for non-Document ExecutionContext.
+    // This doesn't count for ExecutionContexts for shared workers and service
+    // workers.
     static void count(const ExecutionContext*, Feature);
     void count(CSSParserContext, CSSPropertyID);
     void count(Feature);