Simplify locking in HRTFDatabaseLoader

third_party/WebKit/Source/platform/audio/HRTFDatabaseLoader.h

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 35 matching lines @@
 public:
     // Lazily creates a HRTFDatabaseLoader (if not already created) for the given sample-rate
     // and starts loading asynchronously (when created the first time).
     // Returns the HRTFDatabaseLoader.
     // Must be called from the main thread.
     static PassRefPtr<HRTFDatabaseLoader> createAndLoadAsynchronouslyIfNecessary(float sampleRate);
 
     // Both constructor and destructor must be called from the main thread.
     ~HRTFDatabaseLoader();
 
-    // Returns true once the default database has been completely loaded.
-    bool isLoaded();
+    // Returns true once the default database has been completely loaded.  This
+    // must be called from the audio thread.
+    bool isLoaded() { return database(); }
 
     // waitForLoaderThreadCompletion() may be called more than once and is thread-safe.
     void waitForLoaderThreadCompletion();
 
-    HRTFDatabase* database() { return m_hrtfDatabase.get(); }
+    // Returns the database or nullptr if the database doesn't yet exist.  Must
+    // be called from the audio thread.
+    HRTFDatabase* database();
 
     float databaseSampleRate() const { return m_databaseSampleRate; }
 
 private:
     // Both constructor and destructor must be called from the main thread.
     explicit HRTFDatabaseLoader(float sampleRate);
 
     // If it hasn't already been loaded, creates a new thread and initiates asynchronous loading of the default database.
     // This must be called from the main thread.
     void loadAsynchronously();
 
     // Called in asynchronous loading thread.
     void loadTask();
     void cleanupTask(TaskSynchronizer*);
 
     // Holding a m_lock is required when accessing m_hrtfDatabase since we access it from multiple threads.
     Mutex m_lock;
     std::unique_ptr<HRTFDatabase> m_hrtfDatabase;
 
     std::unique_ptr<WebThread> m_thread;
 
     float m_databaseSampleRate;
 };
 
 } // namespace blink
 
 #endif // HRTFDatabaseLoader_h