WebFonts intervention: understand if download time matches the decision

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 93 matching lines @@
 }
 
 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.recordRemoteFont(m_font.get());
+  m_histograms.recordRemoteFont(m_font.get(), m_isInterventionTriggered);
   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()));
@@ skipping 151 matching lines @@
   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) {
+    const FontResource* font,
+    bool isInterventionTriggered) {
   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);
+    recordLoadTimeHistogram(font, duration, isInterventionTriggered);
 
     enum { CORSFail, CORSSuccess, CORSEnumMax };
     int corsValue = font->isCORSFailed() ? CORSFail : CORSSuccess;
     DEFINE_STATIC_LOCAL(EnumerationHistogram, corsHistogram,
                         ("WebFont.CORSSuccess", CORSEnumMax));
     corsHistogram.count(corsValue);
   }
 }
 
 void RemoteFontFaceSource::FontLoadHistograms::maySetDataSource(
     DataSource dataSource) {
   if (m_dataSource != FromUnknown)
     return;
   // Classify as memory cache hit if |m_loadStartTime| is not set, i.e.
   // this RemoteFontFaceSource instance didn't trigger FontResource
   // loading.
   if (m_loadStartTime == 0)
     m_dataSource = FromMemoryCache;
   else
     m_dataSource = dataSource;
 }
 
 void RemoteFontFaceSource::FontLoadHistograms::recordLoadTimeHistogram(
     const FontResource* font,
-    int duration) {
+    int duration,
+    bool isInterventionTriggered) {
   CHECK_NE(FromUnknown, m_dataSource);
 
   if (font->errorOccurred()) {
     DEFINE_STATIC_LOCAL(CustomCountHistogram, loadErrorHistogram,
                         ("WebFont.DownloadTime.LoadError", 0, 10000, 50));
     DEFINE_STATIC_LOCAL(
         CustomCountHistogram, missedCacheLoadErrorHistogram,
         ("WebFont.MissedCache.DownloadTime.LoadError", 0, 10000, 50));
     loadErrorHistogram.count(duration);
     if (m_dataSource == FromNetwork)
@@ skipping 12 matching lines @@
     if (m_dataSource == FromNetwork)
       missedCacheUnder10kHistogram.count(duration);
     return;
   }
   if (size < 50 * 1024) {
     DEFINE_STATIC_LOCAL(CustomCountHistogram, under50kHistogram,
                         ("WebFont.DownloadTime.1.10KBTo50KB", 0, 10000, 50));
     DEFINE_STATIC_LOCAL(
         CustomCountHistogram, missedCacheUnder50kHistogram,
         ("WebFont.MissedCache.DownloadTime.1.10KBTo50KB", 0, 10000, 50));
+    // Breakdowns metrics to understand WebFonts intervention.
+    // Now we only cover this 10KBto50KB range because 70% of requests are
+    // covered in this range, and having metrics for all size cases cost.
+    DEFINE_STATIC_LOCAL(CustomCountHistogram,
+                        missedCacheAndInterventionTriggeredUnder50kHistogram,
+                        ("WebFont.MissedCacheAndInterventionTriggered."
+                         "DownloadTime.1.10KBTo50KB",
+                         0, 10000, 50));
+    DEFINE_STATIC_LOCAL(CustomCountHistogram,
+                        missedCacheAndInterventionNotTriggeredUnder50kHistogram,
+                        ("WebFont.MissedCacheAndInterventionNotTriggered."
+                         "DownloadTime.1.10KBTo50KB",
+                         0, 10000, 50));
     under50kHistogram.count(duration);
-    if (m_dataSource == FromNetwork)
+    if (m_dataSource == FromNetwork) {
       missedCacheUnder50kHistogram.count(duration);
+      if (isInterventionTriggered)
+        missedCacheAndInterventionTriggeredUnder50kHistogram.count(duration);
+      else
+        missedCacheAndInterventionNotTriggeredUnder50kHistogram.count(duration);
+    }
     return;
   }
   if (size < 100 * 1024) {
     DEFINE_STATIC_LOCAL(CustomCountHistogram, under100kHistogram,
                         ("WebFont.DownloadTime.2.50KBTo100KB", 0, 10000, 50));
     DEFINE_STATIC_LOCAL(
         CustomCountHistogram, missedCacheUnder100kHistogram,
         ("WebFont.MissedCache.DownloadTime.2.50KBTo100KB", 0, 10000, 50));
     under100kHistogram.count(duration);
     if (m_dataSource == FromNetwork)
@@ skipping 55 matching lines @@
       return Miss;
     case FromUnknown:
     // Fall through.
     default:
       NOTREACHED();
   }
   return Miss;
 }
 
 }  // namespace blink