Force all experiment enabled checks to use ExperimentalFeatures

third_party/WebKit/Source/core/experiments/Experiments.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 Experiments_h
 #define Experiments_h
 
 #include "core/CoreExport.h"
 #include "core/dom/DOMException.h"
 #include "core/dom/ExecutionContext.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
 // The Experimental Framework (EF) provides limited access to experimental APIs,
-// on a per-origin basis.  This class provides an interface to API implementers,
-// for checking if the experimental API should be enabled for the current
-// context.
+// on a per-origin basis.  This class provides the implementation to check if
+// the experimental API should be enabled for the current context.  This class
+// is not for direct use by API implementers.  Instead, the ExperimentalFeatures
+// generated class provides a static method for each API to check if it is
+// enabled. Experimental APIs must be defined in RuntimeEnabledFeatures.in,
+// which is used to generate ExperimentalFeatures.h/cpp.
 //
 // Experimental APIs are defined by string names, provided by the implementers.
 // The EF code does not maintain an enum or constant list for experiment names.
 // Instead, the EF validates the name provided by the API implementation against
 // any provided API keys.
 // TODO(chasej): Link to documentation, or provide more detail on keys, .etc
 class CORE_EXPORT Experiments {
 public:
-    static bool isApiEnabled(ExecutionContext*, const String& apiName, String& errorMessage);
     // Creates a NotSupportedError exception with a message explaining to
     // external developers why the API is disabled and how to join API
     // experiments.
     static DOMException* createApiDisabledException(const String& apiName);
 
 private:
+    friend class ExperimentalFeatures;
+    friend class ExperimentsTest;
+
     explicit Experiments();
+
+    static bool isApiEnabled(ExecutionContext*, const String& apiName, String* errorMessage);
 };
 
 } // namespace blink
 
 #endif // Experiments_h