Add a private API method metricsPrivate.getFieldTrial(), which returns

chrome/browser/extensions/api/metrics_private/metrics_private_api.h

 // Copyright (c) 2012 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 CHROME_BROWSER_EXTENSIONS_API_METRICS_PRIVATE_METRICS_PRIVATE_API_H_
 #define CHROME_BROWSER_EXTENSIONS_API_METRICS_PRIVATE_METRICS_PRIVATE_API_H_
 
 #include <string>
 
 #include "base/metrics/histogram.h"
 #include "chrome/browser/extensions/extension_function.h"
 
 namespace extensions {
 
 class MetricsPrivateGetIsCrashReportingEnabledFunction
     : public SyncExtensionFunction {
  public:
   DECLARE_EXTENSION_FUNCTION("metricsPrivate.getIsCrashReportingEnabled",
                              METRICSPRIVATE_GETISCRASHRECORDINGENABLED)
 
  protected:
   virtual ~MetricsPrivateGetIsCrashReportingEnabledFunction() {}
 
   // ExtensionFunction:
   virtual bool RunImpl() OVERRIDE;
 };
 
+class MetricsPrivateGetFieldTrialFunction : public SyncExtensionFunction {
+ public:
+  DECLARE_EXTENSION_FUNCTION("metricsPrivate.getFieldTrial",
+                             METRICSPRIVATE_GETFIELDTRIAL)
+
+ protected:
+  virtual ~MetricsPrivateGetFieldTrialFunction() {}
+
+  // ExtensionFunction:
+  virtual bool RunImpl() OVERRIDE;
+};
+
 class MetricsPrivateRecordUserActionFunction : public SyncExtensionFunction {
  public:
   DECLARE_EXTENSION_FUNCTION("metricsPrivate.recordUserAction",
                              METRICSPRIVATE_RECORDUSERACTION)
 
  protected:
   virtual ~MetricsPrivateRecordUserActionFunction() {}
 
   // ExtensionFunction:
   virtual bool RunImpl() OVERRIDE;
@@ skipping 108 matching lines @@
  protected:
   virtual ~MetricsPrivateRecordLongTimeFunction() {}
 
   // ExtensionFunction:
   virtual bool RunImpl() OVERRIDE;
 };
 
 } // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_METRICS_PRIVATE_METRICS_PRIVATE_API_H_