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

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

 // 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.
 
 #ifndef RemoteFontFaceSource_h
 #define RemoteFontFaceSource_h
 
 #include "core/css/CSSFontFaceSource.h"
 #include "core/fetch/FontResource.h"
 #include "wtf/Allocator.h"
@@ skipping 56 matching lines @@
 
         FontLoadHistograms(DataSource dataSource) : m_loadStartTime(0), m_blankPaintTime(0), m_isLongLimitExceeded(false), m_dataSource(dataSource) { }
         void loadStarted();
         void fallbackFontPainted(DisplayPeriod);
         void fontLoaded(bool isInterventionTriggered);
         void longLimitExceeded(bool isInterventionTriggered);
         void recordFallbackTime(const FontResource*);
         void recordRemoteFont(const FontResource*);
         bool hadBlankText() { return m_blankPaintTime; }
         DataSource dataSource() { return m_dataSource; }
-        void maySetDataSource(DataSource dataSource) { m_dataSource = (m_dataSource != FromUnknown) ? m_dataSource : dataSource; }
+        // Classify as memory cache hit if |m_loadStartTime| is not set, i.e.
+        // this RemoteFontFaceSource instance didn't trigger FontResource
+        // loading.
+        void maySetDataSource(DataSource dataSource) { m_dataSource = (m_dataSource != FromUnknown) ? m_dataSource : (m_loadStartTime == 0) ? FromMemoryCache : dataSource; }

[kouhei (in TOK), 2016/09/30 01:18:35]

Please implement this in .cpp file, not nesting ?: op.

     private:
         void recordLoadTimeHistogram(const FontResource*, int duration);
         void recordInterventionResult(bool isTriggered);
         CacheHitMetrics dataSourceMetricsValue();
         double m_loadStartTime;
         double m_blankPaintTime;
         bool m_isLongLimitExceeded;
         DataSource m_dataSource;
     };
 
     void switchToSwapPeriod();
     void switchToFailurePeriod();
     bool shouldTriggerWebFontsIntervention();
 
     Member<FontResource> m_font;
     Member<CSSFontSelector> m_fontSelector;
     const FontDisplay m_display;
     DisplayPeriod m_period;
     FontLoadHistograms m_histograms;
     bool m_isInterventionTriggered;
 };
 
 } // namespace blink
 
 #endif