[Origin Trials] Install origin trial bindings on V8 context conditionally

third_party/WebKit/Source/core/origin_trials/OriginTrialContext.h

 // Copyright 2015 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 OriginTrialContext_h
 #define OriginTrialContext_h
 
 #include "core/CoreExport.h"
 #include "platform/Supplementable.h"
 #include "wtf/HashSet.h"
@@ skipping 52 matching lines @@
     static std::unique_ptr<Vector<String>> getTokens(ExecutionContext*);
 
     void addToken(const String& token);
     void addTokens(const Vector<String>& tokens);
 
     // Returns true if the feature should be considered enabled for the current
     // execution context. If non-null, the |errorMessage| parameter will be used
     // to provide a message for features that are not enabled.
     bool isFeatureEnabled(const String& featureName, String* errorMessage);
 
+    // Installs JavaScript bindings for any features which should be enabled by
+    // the current set of trial tokens. This method is idempotent; only features
+    // which have been enabled since the last time it was run will be installed.
+    // If the V8 context for the host execution context has not been
+    // initialized, then this method will return without doing anything.
+    void initializePendingTrials();

[chasej, 2016/05/31 15:42:13]

Nit: maybe this should be named "initializePendingFeatures"? While the class is
OriginTrialContext, the implementation generally refers to features, not trials.

[iclelland, 2016/05/31 16:03:44]

Done.

+
     void setFeatureBindingsInstalled(const String& featureName);
     bool featureBindingsInstalled(const String& featureName);
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     Member<ExecutionContext> m_host;
     Vector<String> m_tokens;
     WebTrialTokenValidator* m_trialTokenValidator;
 
@@ skipping 18 matching lines @@
 
     // Records whether an error message has been generated, for each feature
     // name. Since these messages are generally written to the console, this is
     // used to avoid cluttering the console with messages on every access.
     HashSet<String> m_errorMessageGeneratedForFeature;
 };
 
 } // namespace blink
 
 #endif // OriginTrialContext_h