Initial import of Widevine Common Encryption DRM engine

Builds libwvmdrmengine.so, which is loaded by the new
MediaDrm APIs to support playback of Widevine/CENC
protected content.

Change-Id: I6f57dd37083dfd96c402cb9dd137c7d74edc8f1c

libwvdrmengine/cdm/core/include/lock.h

@@ -0,0 +1,54 @@
+// Copyright 2013 Google Inc. All Rights Reserved.
+//
+// Lock - Platform independent interface for a Mutex class
+//
+#ifndef CDM_BASE_LOCK_H_
+#define CDM_BASE_LOCK_H_
+
+#include "wv_cdm_types.h"
+
+namespace wvcdm {
+
+// Simple lock class. The implementation is platform dependent.
+//
+// The lock must be unlocked by the thread that locked it.
+// The lock is also not recursive (ie. cannot be taken multiple times).
+class Lock {
+ public:
+  Lock();
+  ~Lock();
+
+  void Acquire();
+  void Release();
+
+  // Acquires a lock if not held and returns true.
+  // Returns false if the lock is held by another thread.
+  bool Try();
+
+  friend class AutoLock;
+
+ private:
+  class Impl;
+  Impl *impl_;
+
+  CORE_DISALLOW_COPY_AND_ASSIGN(Lock);
+};
+
+// Manages the lock automatically. It will be locked when AutoLock
+// is constructed and release when AutoLock goes out of scope
+class AutoLock {
+ public:
+  explicit AutoLock(Lock& lock);
+  explicit AutoLock(Lock* lock);
+  ~AutoLock();
+
+ private:
+  class Impl;
+  Impl *impl_;
+
+  CORE_DISALLOW_COPY_AND_ASSIGN(AutoLock);
+};
+
+};  // namespace wvcdm
+
+#endif  // CDM_BASE_LOCK_H_