Add PPAPI decryptor implementation.

ppapi/cpp/private/content_decryptor_private.h

+// Copyright (c) 2012 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 PPAPI_CPP_PRIVATE_CONTENT_DECRYPTOR_PRIVATE_H_
+#define PPAPI_CPP_PRIVATE_CONTENT_DECRYPTOR_PRIVATE_H_
+
+#include "ppapi/cpp/instance_handle.h"
+#include "ppapi/cpp/var.h"
+#include "ppapi/cpp/var_array_buffer.h"
+#include "ppapi/cpp/dev/buffer_dev.h"
+#include "ppapi/c/private/ppb_content_decryptor_private.h"
+#include "ppapi/c/private/ppp_content_decryptor_private.h"

[dmichael (off chromium), 2012/08/15 17:44:37]

nit: include order. The /c/ stuff should come first, and cpp/dev should come in
alphabetical order, too.

[Tom Finegan, 2012/08/16 03:10:48]

Done.

+
+namespace pp {
+
+class Instance;
+
+class ContentDecryptor_Private {
+ public:
+  explicit ContentDecryptor_Private(Instance* instance);
+  virtual ~ContentDecryptor_Private();
+
+  // PPP_ContentDecryptor_Private functions exposed as virtual functions
+  // for you to override.
+  virtual bool GenerateKeyRequest(const std::string& key_system,

[dmichael (off chromium), 2012/08/15 17:44:37]

Re-thinking it, if you just have to turn around and pass the key_system back to
another call, it may make sense to leave it as pp::Var. It's slightly less
efficient to do it this way, because we'll end up making a new Var and copying
the contents of key_system (same for session_id and other string var arguments
that get passed right back to the browser).

No need to change it for now, just something to keep in mind as you write to
this API. It's kind of a tradeoff, since std::string is certainly friendlier.

[Tom Finegan, 2012/08/16 03:10:48]

It's going to require extraction to a string within the wrapper anyway--
decryption module wrapped by the plugin will be expecting a string (I think).

[dmichael (off chromium), 2012/08/16 17:02:28]

My point was that some of these strings will *also* be sent back to the browser
as Vars. So you could extract the string within GenerateKeyRequest to send to
the CDM, but send the same Var back to the browser, so that we don't have an
extra string->Var conversion. The performance savings would probably be pretty
slight, though, so the way you have it is good.

[Tom Finegan, 2012/08/16 18:10:58]

Added a TODO re this being an optimization.

+                                  pp::VarArrayBuffer init_data) = 0;
+  virtual bool AddKey(const std::string& session_id,
+                      pp::VarArrayBuffer key) = 0;
+  virtual bool CancelKeyRequest(const std::string& session_id) = 0;
+  virtual bool Decrypt(pp::Buffer_Dev encrypted_buffer,
+                       int32_t request_id) = 0;
+  virtual bool DecryptAndDecode(pp::Buffer_Dev encrypted_buffer,
+                                int32_t request_id) = 0;
+
+  // PPB_ContentDecryptor_Private methods for passing data from the decryptor
+  // to the browser.
+  void NeedKey(const std::string& key_system,
+               const std::string& session_id,
+               const std::string& init_data);
+  void KeyAdded(const std::string& key_system,
+                const std::string& session_id);
+  void KeyMessage(const std::string& key_system,
+                  const std::string& session_id,
+                  pp::Buffer_Dev message,
+                  const std::string& default_url);
+  void KeyError(const std::string& key_system,
+                const std::string& session_id,
+                int32_t media_error,
+                int32_t system_code);
+  void DeliverBlock(pp::Buffer_Dev decrypted_block,
+                    int32_t request_id);
+  void DeliverFrame(pp::Buffer_Dev decrypted_frame,
+                    int32_t request_id);
+  void DeliverSamples(pp::Buffer_Dev decrypted_samples,
+                      int32_t request_id);
+
+ private:
+  InstanceHandle associated_instance_;
+};
+
+}  // namespace pp
+
+#endif  // PPAPI_CPP_PRIVATE_CONTENT_DECRYPTOR_PRIVATE_H_