Fix race condition-y Finalize w/ extreme predjudice

android_webview/browser/aw_metrics_service_client.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 ANDROID_WEBVIEW_BROWSER_AW_METRICS_SERVICE_CLIENT_IMPL_H_
 #define ANDROID_WEBVIEW_BROWSER_AW_METRICS_SERVICE_CLIENT_IMPL_H_
 
 #include "android_webview/browser/aw_metrics_service_client.h"
 
 #include <string>
@@ skipping 13 matching lines @@
 struct ClientInfo;
 class MetricsStateManager;
 }
 
 namespace net {
 class URLRequestContextGetter;
 }
 
 namespace android_webview {
 
-// This singleton manages metrics for an app using any number of WebViews.
-// Metrics is turned on and off by the homonymous Java class. It should only be
-// used on the main thread. In particular, Initialize, Finalize, and
-// SetMetricsEnabled must be called from the same thread, in order to prevent
-// enable/disable race conditions, and because MetricsService is
-// single-threaded.
+// This singleton manages metrics for an app using any number of WebViews. The
+// homonymous Java class is responsible for turning metrics on and off. This
+// singleton must always be used on the same thread. (Currently the UI thread
+// is enforced, but it could be any thread.) This is to prevent enable/disable
+// race conditions, and because MetricsService is single-threaded.
+// Initialization is asynchronous; even after Initialize has returned, some
+// methods may not be ready to use (see below).
 class AwMetricsServiceClient : public metrics::MetricsServiceClient {
   friend struct base::DefaultLazyInstanceTraits<AwMetricsServiceClient>;
 
  public:
+  // These may be called at any time.
   static AwMetricsServiceClient* GetInstance();
-
   void Initialize(PrefService* pref_service,
                   net::URLRequestContextGetter* request_context,
                   const base::FilePath guid_file_path);
-  void Finalize();
   void SetMetricsEnabled(bool enabled);
 
-  // metrics::MetricsServiceClient implementation
+  // These implement metrics::MetricsServiceClient. They must not be called
+  // until initialization has asynchronously finished.
   metrics::MetricsService* GetMetricsService() override;
   void SetMetricsClientId(const std::string& client_id) override;
   void OnRecordingDisabled() override;
   bool IsOffTheRecordSessionActive() override;
   int32_t GetProduct() override;
   std::string GetApplicationLocale() override;
   bool GetBrand(std::string* brand_code) override;
   metrics::SystemProfileProto::Channel GetChannel() override;
   std::string GetVersionString() override;
   void OnLogUploadComplete() override;
@@ skipping 19 matching lines @@
   net::URLRequestContextGetter* request_context_;
   scoped_ptr<metrics::MetricsStateManager> metrics_state_manager_;
   scoped_ptr<metrics::MetricsService> metrics_service_;
 
   DISALLOW_COPY_AND_ASSIGN(AwMetricsServiceClient);
 };
 
 }  // namespace android_webview
 
 #endif  // ANDROID_WEBVIEW_BROWSER_AW_METRICS_SERVICE_CLIENT_IMPL_H_