Permissions: add UMA for navigator.permissions.query() usage.

Source/modules/permissions/Permissions.idl

Index: Source/modules/permissions/Permissions.idl
diff --git a/Source/modules/permissions/Permissions.idl b/Source/modules/permissions/Permissions.idl
index 89f7dfd085feaf198c4d532d4c1d92001f12a072..bfe878f56e9b609fa28bdd3b207f67bf823a8ce2 100644
--- a/Source/modules/permissions/Permissions.idl
+++ b/Source/modules/permissions/Permissions.idl
@@ -10,5 +10,5 @@
     GarbageCollected,
     RuntimeEnabled=Permissions
 ] interface Permissions {
-    [CallWith=ScriptState] Promise<PermissionStatus> query(object permission);
+    [CallWith=ScriptState, MeasureAs=PermissionsQuery] Promise<PermissionStatus> query(object permission);

[philipj_slow, 2015/04/03 16:49:39]

As of https://codereview.chromium.org/877523004 it's possible to simply use
[Measure], which generates the name. I'd use it wherever possible.

[mlamouri (slow - plz ping), 2015/04/03 17:49:48]

Done.

 };