Add metrics for style update time before FCP.

third_party/WebKit/Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All
  * rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
@@ skipping 38 matching lines @@
 #include "core/SVGElementFactory.h"
 #include "core/SVGNames.h"
 #include "core/XMLNSNames.h"
 #include "core/XMLNames.h"
 #include "core/animation/CompositorPendingAnimations.h"
 #include "core/animation/DocumentAnimations.h"
 #include "core/animation/DocumentTimeline.h"
 #include "core/css/CSSFontSelector.h"
 #include "core/css/CSSStyleDeclaration.h"
 #include "core/css/CSSStyleSheet.h"
+#include "core/css/CSSTiming.h"
 #include "core/css/FontFaceSet.h"
 #include "core/css/MediaQueryMatcher.h"
 #include "core/css/PropertyRegistry.h"
 #include "core/css/StylePropertySet.h"
 #include "core/css/StyleSheetContents.h"
 #include "core/css/StyleSheetList.h"
 #include "core/css/invalidation/StyleInvalidator.h"
 #include "core/css/parser/CSSParser.h"
 #include "core/css/resolver/FontBuilder.h"
 #include "core/css/resolver/StyleResolver.h"
@@ skipping 1933 matching lines @@
 void Document::updateActiveStyle() {
   DCHECK(isActive());
   DCHECK(isMainThread());
   TRACE_EVENT0("blink", "Document::updateActiveStyle");
   styleEngine().updateActiveStyle();
 }
 
 void Document::updateStyle() {
   DCHECK(!view()->shouldThrottleRendering());
   TRACE_EVENT_BEGIN0("blink,blink_style", "Document::updateStyle");
-  SCOPED_BLINK_UMA_HISTOGRAM_TIMER("Style.UpdateTime");
+  double startTime = monotonicallyIncreasingTime();
 
   unsigned initialElementCount = styleEngine().styleForElementCount();
 
   HTMLFrameOwnerElement::UpdateSuspendScope suspendWidgetHierarchyUpdates;
   m_lifecycle.advanceTo(DocumentLifecycle::InStyleRecalc);
 
   StyleRecalcChange change = NoChange;
   if (getStyleChangeType() >= SubtreeStyleChange)
     change = Force;
 
@@ skipping 51 matching lines @@
   if (shouldRecordStats) {
     TRACE_EVENT_END2("blink,blink_style", "Document::updateStyle",
                      "resolverAccessCount",
                      styleEngine().styleForElementCount() - initialElementCount,
                      "counters", styleEngine().stats()->toTracedValue());
   } else {
     TRACE_EVENT_END1(
         "blink,blink_style", "Document::updateStyle", "resolverAccessCount",
         styleEngine().styleForElementCount() - initialElementCount);
   }
+
+  double updateDurationSeconds = monotonicallyIncreasingTime() - startTime;
+  DEFINE_STATIC_LOCAL(CustomCountHistogram, updateHistogram,
+                      ("Style.UpdateTime", 0, 10000000, 50));
+  updateHistogram.count(updateDurationSeconds * 1000 * 1000);
+  CSSTiming::from(*this).recordUpdateDuration(updateDurationSeconds);
 }
 
 void Document::notifyLayoutTreeOfSubtreeChanges() {
   if (!layoutViewItem().wasNotifiedOfSubtreeChange())
     return;
 
   m_lifecycle.advanceTo(DocumentLifecycle::InLayoutSubtreeChange);
 
   layoutViewItem().handleSubtreeModifications();
   DCHECK(!layoutViewItem().wasNotifiedOfSubtreeChange());
@@ skipping 4452 matching lines @@
 }
 
 void showLiveDocumentInstances() {
   WeakDocumentSet& set = liveDocumentSet();
   fprintf(stderr, "There are %u documents currently alive:\n", set.size());
   for (Document* document : set)
     fprintf(stderr, "- Document %p URL: %s\n", document,
             document->url().getString().utf8().data());
 }
 #endif