Reset some UMA stability stats on a version change.

chrome/browser/metrics/plugin_metrics_provider.h

 // 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.
 
 #ifndef CHROME_BROWSER_METRICS_PLUGIN_METRICS_PROVIDER_H_
 #define CHROME_BROWSER_METRICS_PLUGIN_METRICS_PROVIDER_H_
 
 #include <map>
 #include <vector>
 
@@ skipping 25 matching lines @@
 
   // Fetches plugin information data asynchronously and calls |done_callback|
   // when done.
   void GetPluginInformation(const base::Closure& done_callback);
 
   // metrics::MetricsDataProvider:
   virtual void ProvideSystemProfileMetrics(
       metrics::SystemProfileProto* system_profile_proto) OVERRIDE;
   virtual void ProvideStabilityMetrics(
       metrics::SystemProfileProto* system_profile_proto) OVERRIDE;
+  virtual void ClearSavedStabilityMetrics() OVERRIDE;
 
   // Notifies the provider about an error loading the plugin at |plugin_path|.
   void LogPluginLoadingError(const base::FilePath& plugin_path);
 
   // Sets this provider's list of plugins, exposed for testing.
   void SetPluginsForTesting(const std::vector<content::WebPluginInfo>& plugins);
 
   // Returns true if process of type |type| should be counted as a plugin
   // process, and false otherwise.
   static bool IsPluginProcess(int process_type);
@@ skipping 45 matching lines @@
 
   // Buffer of child process notifications for quick access.
   std::map<base::string16, ChildProcessStats> child_process_stats_buffer_;
 
   base::WeakPtrFactory<PluginMetricsProvider> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PluginMetricsProvider);
 };
 
 #endif  // CHROME_BROWSER_METRICS_PLUGIN_METRICS_PROVIDER_H_