Remove histogram in ShadowRoot constructor

Source/core/dom/shadow/ShadowRoot.cpp

 /*
  * Copyright (C) 2011 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 51 matching lines @@
     , m_prev(0)
     , m_next(0)
     , m_numberOfStyles(0)
     , m_applyAuthorStyles(false)
     , m_resetStyleInheritance(false)
     , m_type(type)
     , m_registeredWithParentShadowRoot(false)
     , m_descendantInsertionPointsIsValid(false)
 {
     ScriptWrappable::init(this);
-
-    if (type == ShadowRoot::AuthorShadowRoot) {
-        ShadowRootUsageOriginType usageType = document.url().protocolIsInHTTPFamily() ? ShadowRootUsageOriginWeb : ShadowRootUsageOriginNotWeb;
-        blink::Platform::current()->histogramEnumeration("WebCore.ShadowRoot.constructor", usageType, ShadowRootUsageOriginMax);
-    }
 }
 
 ShadowRoot::~ShadowRoot()
 {
     ASSERT(!m_prev);
     ASSERT(!m_next);
 
     if (m_shadowRootRareData && m_shadowRootRareData->styleSheets())
         m_shadowRootRareData->styleSheets()->detachFromDocument();
 
@@ skipping 388 matching lines @@
 {
     ensureShadowRootRareData()->setChildrenAffectedByFirstChildRules(true);
 }
 
 void ShadowRoot::setChildrenAffectedByLastChildRules()
 {
     ensureShadowRootRareData()->setChildrenAffectedByLastChildRules(true);
 }
 
 }