[Cronet] Make StartNetLog and StopNetLog synchronous in Cronet

components/cronet/android/cronet_url_request_context_adapter.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 COMPONENTS_CRONET_ANDROID_CRONET_URL_REQUEST_CONTEXT_ADAPTER_H_
 #define COMPONENTS_CRONET_ANDROID_CRONET_URL_REQUEST_CONTEXT_ADAPTER_H_
 
 #include <jni.h>
 #include <stdint.h>
 
@@ skipping 58 matching lines @@
 
   // Posts a task that might depend on the context being initialized
   // to the network thread.
   void PostTaskToNetworkThread(const tracked_objects::Location& posted_from,
                                const base::Closure& callback);
 
   bool IsOnNetworkThread() const;
 
   net::URLRequestContext* GetURLRequestContext();
 
+  // Starts NetLog logging to file. This can be called on any thread.
   void StartNetLogToFile(JNIEnv* env,
                          const base::android::JavaParamRef<jobject>& jcaller,
                          const base::android::JavaParamRef<jstring>& jfile_name,
                          jboolean jlog_all);
 
+  // Stops NetLog logging to file. This can be called on any thread. This will
+  // flush any remaining writes to disk.
   void StopNetLog(JNIEnv* env,
                   const base::android::JavaParamRef<jobject>& jcaller);
 
   // Default net::LOAD flags used to create requests.
   int default_load_flags() const { return default_load_flags_; }
 
   // Called on main Java thread to initialize URLRequestContext.
   void InitRequestContextOnMainThread();
 
   // Enables the network quality estimator and optionally configures it to
@@ skipping 23 matching lines @@
       const base::android::ScopedJavaGlobalRef<jobject>&
           jcronet_url_request_context);
 
   // Runs a task that might depend on the context being initialized.
   // This method should only be run on the network thread.
   void RunTaskAfterContextInitOnNetworkThread(
       const base::Closure& task_to_run_after_context_init);
 
   scoped_refptr<base::SingleThreadTaskRunner> GetNetworkTaskRunner() const;
 
-  void StartNetLogToFileOnNetworkThread(const std::string& file_name,
-                                        bool log_all);
-
-  void StopNetLogOnNetworkThread();
-
   // Gets the file thread. Create one if there is none.
   base::Thread* GetFileThread();
 
   // Instantiate and configure the network quality estimator. For default
   // behavior, parameters should be set to false; otherwise the estimator
   // can be configured to observe requests to localhost, as well as to use
   // observe smaller responses when estimating throughput.
   void EnableNetworkQualityEstimatorOnNetworkThread(
       bool use_local_host_requests,
       bool use_smaller_responses);
@@ skipping 11 matching lines @@
       int32_t throughput_kbps,
       const base::TimeTicks& timestamp,
       net::NetworkQualityObservationSource source) override;
 
   // Network thread is owned by |this|, but is destroyed from java thread.
   base::Thread* network_thread_;
 
   // File thread should be destroyed last.
   std::unique_ptr<base::Thread> file_thread_;
 
-  // |write_to_file_observer_| and |context_| should only be accessed on
-  // network thread.
+  // |write_to_file_observer_| should only be accessed with
+  // |write_to_file_observer_lock_|.
   std::unique_ptr<net::WriteToFileNetLogObserver> write_to_file_observer_;
+  base::Lock write_to_file_observer_lock_;
 
   // |pref_service_| should outlive the HttpServerPropertiesManager owned by
   // |context_|.
   std::unique_ptr<PrefService> pref_service_;
   std::unique_ptr<net::URLRequestContext> context_;
   std::unique_ptr<net::ProxyConfigService> proxy_config_service_;
   scoped_refptr<JsonPrefStore> json_pref_store_;
   net::HttpServerPropertiesManager* http_server_properties_manager_;
 
   // |sdch_owner_| should be destroyed before |json_pref_store_|, because
@@ skipping 18 matching lines @@
 #if defined(DATA_REDUCTION_PROXY_SUPPORT)
   std::unique_ptr<CronetDataReductionProxy> data_reduction_proxy_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(CronetURLRequestContextAdapter);
 };
 
 }  // namespace cronet
 
 #endif  // COMPONENTS_CRONET_ANDROID_CRONET_URL_REQUEST_CONTEXT_ADAPTER_H_