Add metrics for usage of permission features from iframes in blink

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

 /*
  * Copyright (C) 2012 Google, Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 712 matching lines @@
     UseCounter::countDeprecation(document.frame(), feature);
 }
 
 void UseCounter::countDeprecationIfNotPrivateScript(v8::Isolate* isolate, ExecutionContext* context, Feature feature)
 {
     if (DOMWrapperWorld::current(isolate).isPrivateScriptIsolatedWorld())
         return;
     UseCounter::countDeprecation(context, feature);
 }
 
+void UseCounter::countCrossOriginIframe(const Document& document, Feature feature)
+{
+    Frame* frame = document.frame();
+    if (!frame)
+        return;
+    SecurityOrigin* securityOrigin = frame->securityContext()->securityOrigin();
+    Frame* parent = frame->tree().parent();
+    if (parent && !securityOrigin->canAccess(parent->securityContext()->securityOrigin()))

[mlamouri (slow - plz ping), 2016/01/19 17:54:48]

canAccess() is not exactly "cross origin". Maybe this should be specified in the
header.

[raymes, 2016/01/20 00:13:12]

Done. Actually you made me realise that this code isn't good enough. We want to
check if the frame has access into the top level document. It may be able to
script into its parent but the parent may be a different origin to the top level
document.

+        count(frame, feature);
+}
+
 static const char* milestoneString(int milestone)
 {
     switch (milestone) {
     case 50:
         return "M50, around April 2016";
     case 53:
         return "M53, around September 2016";
     }
 
     ASSERT_NOT_REACHED();
@@ skipping 268 matching lines @@
 UseCounter* UseCounter::getFrom(const StyleSheetContents* sheetContents)
 {
     // FIXME: We may want to handle stylesheets that have multiple owners
     //        https://crbug.com/242125
     if (sheetContents && sheetContents->hasSingleOwnerNode())
         return getFrom(sheetContents->singleOwnerDocument());
     return 0;
 }
 
 } // namespace blink