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

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

Index: third_party/WebKit/Source/core/css/RemoteFontFaceSource.cpp
diff --git a/third_party/WebKit/Source/core/css/RemoteFontFaceSource.cpp b/third_party/WebKit/Source/core/css/RemoteFontFaceSource.cpp
index 638504edc43eb4d7de3a6f295989eb95929a4d1c..66b833a9c86ed4591b34b0a31827f295139c6a82 100644
--- a/third_party/WebKit/Source/core/css/RemoteFontFaceSource.cpp
+++ b/third_party/WebKit/Source/core/css/RemoteFontFaceSource.cpp
@@ -107,7 +107,7 @@ bool RemoteFontFaceSource::isValid() const
 
 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);
 
@@ -254,8 +254,7 @@ void RemoteFontFaceSource::FontLoadHistograms::fontLoaded(bool isInterventionTri
 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);
 }
 
@@ -275,6 +274,7 @@ void RemoteFontFaceSource::FontLoadHistograms::recordRemoteFont(const FontResour
     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);