Implement "Key Presence" step in "Encrypted Block Encounted" algorithm in EME.

webkit/media/crypto/proxy_decryptor.h

Index: webkit/media/crypto/proxy_decryptor.h
diff --git a/webkit/media/crypto/proxy_decryptor.h b/webkit/media/crypto/proxy_decryptor.h
index 61360ebaceb5f33235cdef782ae9d719ba2bf6a7..a4638af01967c2e0d1c5a7255e12b1c56d46147b 100644
--- a/webkit/media/crypto/proxy_decryptor.h
+++ b/webkit/media/crypto/proxy_decryptor.h
@@ -6,11 +6,16 @@
 #define WEBKIT_MEDIA_CRYPTO_PROXY_DECRYPTOR_H_
 
 #include <string>
+#include <vector>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/synchronization/lock.h"
 #include "media/base/decryptor.h"
 
+namespace base {
+class MessageLoopProxy;
+}
+
 namespace media {
 class DecryptorClient;
 }
@@ -33,6 +38,10 @@ class ProxyDecryptor : public media::Decryptor {
                  WebKit::WebFrame* web_frame);
   virtual ~ProxyDecryptor();
 
+  void set_decryptor_for_testing(scoped_ptr<media::Decryptor> decryptor) {
+    decryptor_ = decryptor.Pass();
+  }
+
   // media::Decryptor implementation.
   virtual void GenerateKeyRequest(const std::string& key_system,
                                   const uint8* init_data,
@@ -47,26 +56,40 @@ class ProxyDecryptor : public media::Decryptor {
                                 const std::string& session_id) OVERRIDE;
   virtual void Decrypt(const scoped_refptr<media::DecoderBuffer>& encrypted,
                        const DecryptCB& decrypt_cb) OVERRIDE;
+  virtual void Stop() OVERRIDE;
 
  private:
   scoped_ptr<media::Decryptor> CreatePpapiDecryptor(
       const std::string& key_system);
   scoped_ptr<media::Decryptor> CreateDecryptor(const std::string& key_system);
 
+  // Helper function that makes sure decryptor_->Decrypt() runs on the
+  // |message_loop|.
+  void DecryptOnMessageLoop(
+      const scoped_refptr<base::MessageLoopProxy>& message_loop_proxy,
+      const scoped_refptr<media::DecoderBuffer>& encrypted,
+      const media::Decryptor::DecryptCB& decrypt_cb);
+
+  // Callback used to pass into decryptor_->Decrypt().
+  void OnBufferDecrypted(
+      const scoped_refptr<base::MessageLoopProxy>& message_loop_proxy,
+      const scoped_refptr<media::DecoderBuffer>& encrypted,
+      const media::Decryptor::DecryptCB& decrypt_cb,
+      media::Decryptor::DecryptStatus status,
+      const scoped_refptr<media::DecoderBuffer>& decrypted);
+
   media::DecryptorClient* client_;
 
   // Needed to create the PpapiDecryptor.
   WebKit::WebMediaPlayerClient* web_media_player_client_;
   WebKit::WebFrame* web_frame_;
 
-  // Protects the |decryptor_|. The Decryptor interface specifies that the
-  // Decrypt() function will be called on the decoder thread and all other
-  // methods on the renderer thread. The |decryptor_| itself is thread safe
-  // when this rule is obeyed. This lock is solely to prevent the race condition
-  // between setting the |decryptor_| in GenerateKeyRequest() and using it in
-  // Decrypt().
+  // Protects the |decryptor_| and |pending_decrypt_closures_|. Note that
+  // |decryptor_| itself should be thread safe as per the Decryptor interface.
   base::Lock lock_;
-  scoped_ptr<media::Decryptor> decryptor_;  // Protected by the |lock_|.
+  scoped_ptr<media::Decryptor> decryptor_;
+  std::vector<base::Closure> pending_decrypt_closures_;
+  bool stopped_;
 
   DISALLOW_COPY_AND_ASSIGN(ProxyDecryptor);
 };