Add CSSTiming to collect aggregate PLT-level stats about CSS.

third_party/WebKit/Source/core/css/StyleSheetContents.cpp

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2006, 2007, 2012 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 #include "core/css/StyleSheetContents.h"
 
 #include "core/css/CSSStyleSheet.h"
+#include "core/css/CSSTiming.h"
 #include "core/css/StylePropertySet.h"
 #include "core/css/StyleRule.h"
 #include "core/css/StyleRuleImport.h"
 #include "core/css/StyleRuleNamespace.h"
 #include "core/css/parser/CSSParser.h"
 #include "core/dom/Document.h"
 #include "core/dom/Node.h"
 #include "core/dom/StyleEngine.h"
 #include "core/fetch/CSSStyleSheetResource.h"
 #include "core/frame/UseCounter.h"
@@ skipping 286 matching lines @@
 const AtomicString& StyleSheetContents::namespaceURIFromPrefix(
     const AtomicString& prefix) {
   return m_namespaces.get(prefix);
 }
 
 void StyleSheetContents::parseAuthorStyleSheet(
     const CSSStyleSheetResource* cachedStyleSheet,
     const SecurityOrigin* securityOrigin) {
   TRACE_EVENT1("blink,devtools.timeline", "ParseAuthorStyleSheet", "data",
                InspectorParseAuthorStyleSheetEvent::data(cachedStyleSheet));
-  SCOPED_BLINK_UMA_HISTOGRAM_TIMER("Style.AuthorStyleSheet.ParseTime");
+  double startTimeMS = monotonicallyIncreasingTimeMS();
 
   bool isSameOriginRequest =
       securityOrigin && securityOrigin->canRequest(baseURL());
 
   // When the response was fetched via the Service Worker, the original URL may
   // not be same as the base URL.
   // TODO(horo): When we will use the original URL as the base URL, we can
   // remove this check. crbug.com/553535
   if (cachedStyleSheet->response().wasFetchedViaServiceWorker()) {
     const KURL originalURL(
@@ skipping 12 matching lines @@
   const ResourceResponse& response = cachedStyleSheet->response();
   m_sourceMapURL = response.httpHeaderField(HTTPNames::SourceMap);
   if (m_sourceMapURL.isEmpty()) {
     // Try to get deprecated header.
     m_sourceMapURL = response.httpHeaderField(HTTPNames::X_SourceMap);
   }
 
   CSSParserContext context(parserContext(), UseCounter::getFrom(this));
   CSSParser::parseSheet(context, this, sheetText,
                         RuntimeEnabledFeatures::lazyParseCSSEnabled());
+
+  DEFINE_STATIC_LOCAL(CustomCountHistogram, parseHistogram,
+                      ("Style.AuthorStyleSheet.ParseTime", 0, 10000000, 50));
+  double parseDurationMS = (monotonicallyIncreasingTimeMS() - startTimeMS);
+  parseHistogram.count(parseDurationMS * 1000);
+  if (Document* document = singleOwnerDocument()) {
+    // CSSTiming expects time in seconds.
+    CSSTiming::from(*document).recordAuthorStyleSheetParseTime(parseDurationMS /
+                                                               1000);
+  }
 }
 
 void StyleSheetContents::parseString(const String& sheetText) {
   parseStringAtPosition(sheetText, TextPosition::minimumPosition());
 }
 
 void StyleSheetContents::parseStringAtPosition(
     const String& sheetText,
     const TextPosition& startPosition) {
   CSSParserContext context(parserContext(), UseCounter::getFrom(this));
@@ skipping 301 matching lines @@
   visitor->trace(m_importRules);
   visitor->trace(m_namespaceRules);
   visitor->trace(m_childRules);
   visitor->trace(m_loadingClients);
   visitor->trace(m_completedClients);
   visitor->trace(m_ruleSet);
   visitor->trace(m_referencedFromResource);
 }
 
 }  // namespace blink