Lower the webfont loading priority only if the user is in V2 field trial

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 179 matching lines @@
   m_period = FailurePeriod;
 }
 
 bool RemoteFontFaceSource::shouldTriggerWebFontsIntervention() {
   if (RuntimeEnabledFeatures::webFontsInterventionTriggerEnabled())
     return true;
   if (m_histograms.dataSource() == FontLoadHistograms::FromMemoryCache ||
       m_histograms.dataSource() == FontLoadHistograms::FromDataURL)
     return false;
 
   bool isV2Enabled =

[Takashi Toyoshima, 2017/03/21 08:46:58]

We have same code here.
Can you factor out these checks as a function, isWebFontInterventionV2Enabled()
in anonymous namespace, and use it from both two places?

[tbansal1, 2017/03/21 16:47:16]

Done.

       RuntimeEnabledFeatures::webFontsInterventionV2With2GEnabled() ||
       RuntimeEnabledFeatures::webFontsInterventionV2With3GEnabled() ||
       RuntimeEnabledFeatures::webFontsInterventionV2WithSlow2GEnabled();
 
   bool networkIsSlow =
       isV2Enabled ? isEffectiveConnectionTypeSlowFor(m_fontSelector->document())
                   : isConnectionTypeSlow();
 
   return networkIsSlow && m_display == FontDisplayAuto;
 }
 
 bool RemoteFontFaceSource::isLowPriorityLoadingAllowedForRemoteFont() const {
-  return m_isInterventionTriggered;
+  bool isV2Enabled =
+      RuntimeEnabledFeatures::webFontsInterventionV2With2GEnabled() ||
+      RuntimeEnabledFeatures::webFontsInterventionV2With3GEnabled() ||
+      RuntimeEnabledFeatures::webFontsInterventionV2WithSlow2GEnabled();
+
+  return m_isInterventionTriggered && isV2Enabled;
 }
 
 PassRefPtr<SimpleFontData> RemoteFontFaceSource::createFontData(
     const FontDescription& fontDescription) {
   if (m_period == FailurePeriod || !isValid())
     return nullptr;
   if (!isLoaded())
     return createLoadingFallbackFontData(fontDescription);
   DCHECK(m_customFontData);
 
@@ skipping 254 matching lines @@
       return Miss;
     case FromUnknown:
     // Fall through.
     default:
       NOTREACHED();
   }
   return Miss;
 }
 
 }  // namespace blink