FontLoadHistograms: classify as memory cache hit if FontResource loading not triggered

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

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/css/RemoteFontFaceSource.h"
 
 #include "core/css/CSSCustomFontData.h"
 #include "core/css/CSSFontFace.h"
 #include "core/css/CSSFontSelector.h"
 #include "core/dom/Document.h"
@@ skipping 89 matching lines @@
     return m_font->isLoaded();
 }
 
 bool RemoteFontFaceSource::isValid() const
 {
     return !m_font->errorOccurred();
 }
 
 void RemoteFontFaceSource::notifyFinished(Resource*)
 {
-    m_histograms.maySetDataSource(m_font->response().wasCached() ? FontLoadHistograms::FromDiskCache : FontLoadHistograms::FromNetwork);
+    m_histograms.maySetDataSource(!m_histograms.isLoadStartedCalled() ? FontLoadHistograms::FromMemoryCache : m_font->response().wasCached() ? FontLoadHistograms::FromDiskCache : FontLoadHistograms::FromNetwork);
     m_histograms.recordRemoteFont(m_font.get());
     m_histograms.fontLoaded(m_isInterventionTriggered);
 
     m_font->ensureCustomFontData();
     // FIXME: Provide more useful message such as OTS rejection reason.
     // See crbug.com/97467
     if (m_font->getStatus() == Resource::DecodeError && m_fontSelector->document()) {
         m_fontSelector->document()->addConsoleMessage(ConsoleMessage::create(OtherMessageSource, WarningMessageLevel, "Failed to decode downloaded font: " + m_font->url().elidedString()));
         if (m_font->otsParsingMessage().length() > 1)
             m_fontSelector->document()->addConsoleMessage(ConsoleMessage::create(OtherMessageSource, WarningMessageLevel, "OTS parsing error: " + m_font->otsParsingMessage()));
@@ skipping 126 matching lines @@
 
 void RemoteFontFaceSource::FontLoadHistograms::fontLoaded(bool isInterventionTriggered)
 {
     if (!m_isLongLimitExceeded)
         recordInterventionResult(isInterventionTriggered);
 }
 
 void RemoteFontFaceSource::FontLoadHistograms::longLimitExceeded(bool isInterventionTriggered)
 {
     m_isLongLimitExceeded = true;
-    if (m_dataSource == FromUnknown)
-        m_dataSource = FromNetwork;
+    maySetDataSource(isLoadStartedCalled() ? FromNetwork : FromMemoryCache);

[Kunihiko Sakamoto, 2016/09/29 09:19:26]

Can you put this logic (if m_loadStartTime == 0 then FromMemoryCache) into
maySetDataSource()?

[Shao-Chuan Lee, 2016/09/29 09:31:42]

Done.

     recordInterventionResult(isInterventionTriggered);
 }
 
 void RemoteFontFaceSource::FontLoadHistograms::recordFallbackTime(const FontResource* font)
 {
     if (m_blankPaintTime <= 0)
         return;
     int duration = static_cast<int>(currentTimeMS() - m_blankPaintTime);
     DEFINE_STATIC_LOCAL(CustomCountHistogram, blankTextShownTimeHistogram, ("WebFont.BlankTextShownTime", 0, 10000, 50));
     blankTextShownTimeHistogram.count(duration);
     m_blankPaintTime = -1;
 }
 
 void RemoteFontFaceSource::FontLoadHistograms::recordRemoteFont(const FontResource* font)
 {
     DEFINE_STATIC_LOCAL(EnumerationHistogram, cacheHitHistogram, ("WebFont.CacheHit", CacheHitEnumMax));
     cacheHitHistogram.count(dataSourceMetricsValue());
 
     if (m_dataSource == FromDiskCache || m_dataSource == FromNetwork) {
+        DCHECK_NE(m_loadStartTime, 0);
         int duration = static_cast<int>(currentTimeMS() - m_loadStartTime);
         recordLoadTimeHistogram(font, duration);
 
         enum { CORSFail, CORSSuccess, CORSEnumMax };
         int corsValue = font->isCORSFailed() ? CORSFail : CORSSuccess;
         DEFINE_STATIC_LOCAL(EnumerationHistogram, corsHistogram, ("WebFont.CORSSuccess", CORSEnumMax));
         corsHistogram.count(corsValue);
     }
 }
 
@@ skipping 82 matching lines @@
         return Miss;
     case FromUnknown:
         // Fall through.
     default:
         NOTREACHED();
     }
     return Miss;
 }
 
 } // namespace blink