Add PPAPI decryptor interfaces.

ppapi/api/private/ppp_content_decryptor_private.idl

+/* 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.
+ */
+
+/**
+ * This file defines the <code>PPP_ContentDecryptor_Private</code>
+ * interface.
+ */
+label Chrome {
+  M23 = 0.1
+};
+
+/**
+ * <code>PPP_ContentDecryptor_Private</code> structure contains the function
+ * pointers the decryption plugin MUST implement to provide services needed by
+ * the media stack. This interface provides the plugin side support for v0.1 of

[xhwang, 2012/08/10 16:41:30]

"media stack" seems implementation detail. Maybe just needed by "the browser"?

[Tom Finegan, 2012/08/10 17:13:06]

s/media stack/user agent/. 

I can change it to browser if that's preferred.

+ * the proposed Encrypted Media Extensions: http://goo.gl/rbdnR

[xhwang, 2012/08/10 16:41:30]

ditto: not sure about if short URL is appropriate.

[Tom Finegan, 2012/08/10 17:13:06]

See comment in PPB IDL.

+ *
+ * Note: This is a special interface, only to be used for Content Decryption
+ * Modules, not normal plugins.
+ */
+interface PPP_ContentDecryptor_Private {
+  /**
+   * Generates a key request. key_system specifies the key or licensing system
+   * from which to request the key when the plugin provides access to multiple
+   * systems. init_data is a data buffer containing initialization data from
+   * the media data that is required for use of the plugin's key system(s).
+   *
+   * Note: <code>GenerateKeyRequest()</code> is responsible for creating the
+   * session ID used in other methods on this interface. The session ID will be
+   * provided to the user agent via <code>KeyMessage()</code> on the

[xhwang, 2012/08/10 16:41:30]

"user agent" is the term used in the spec. Should we just use "the browser"
here? 

[Tom Finegan, 2012/08/10 17:13:06]

Not sure, comments welcome! :)

+   * <code>PPB_ContentDecryptor_Private</code> interface.
+   *
+   * @param[in] key_system A <code>PP_Var</code> of type
+   * <code>PP_VARTYPE_STRING</code> containing the name of the key system.
+   *
+   * @param[in] init_data A <code>PP_Var</code> of type
+   * <code>PP_VARTYPE_ARRAYBUFFER</code> containing content specific
+   * initialization data.
+   */
+  PP_Bool GenerateKeyRequest(
+      [in] PP_Instance instance,
+      [in] PP_Var key_system,
+      [in] PP_Var init_data);
+
+  /**
+   * Provides a key or license to the decryptor for decrypting media data in the
+   * stream associated with session_id.
+   *
+   * @param[in] session_id A <code>PP_Var</code> of type
+   * <code>PP_VARTYPE_STRING</code> containing the session ID.
+   *
+   * @param[in] key A <code>PP_Var</code> of type
+   * <code>PP_VARTYPE_ARRAYBUFFER</code> containing the decryption key for the
+   * given session ID.
+   */
+  PP_Bool AddKey(
+      [in] PP_Instance instance,
+      [in] PP_Var session_id,
+      [in] PP_Var key);
+
+  /**
+   * Cancels a pending key request for the specified session ID.
+   *
+   * @param[in] session_id A <code>PP_Var</code> of type
+   * <code>PP_VARTYPE_STRING</code> containing the session ID.
+   */
+  PP_Bool CancelKeyRequest(
+      [in] PP_Instance instance,
+      [in] PP_Var session_id);
+
+  /**
+   * Decrypts the block and returns the unencrypted block via
+   * <code>DeliverBlock()</code> on the
+   * <code>PPB_ContentDecryptor_Private</code> interface. The returned block
+   * contains encoded data.
+   *
+   * @param[in] resource A <code>PP_Resource</code> corresponding to a
+   * <code>PPB_Buffer_Dev</code> resource that contains an encrypted data
+   * block.
+   *
+   * @param[in] request_id A value used by the user agent to associate data
+   * returned via the <code>PPB_ContentDecryptor_Private</code> interface with
+   * decryption method calls.
+   */
+  PP_Bool Decrypt(
+      [in] PP_Instance instance,
+      [in] PP_Resource encrypted_block,
+      [in] uint64_t request_id);
+
+  /**
+   * Decrypts the block, decodes it, and returns the unencrypted raw (decoded)

[xhwang, 2012/08/10 16:41:30]

s/raw/uncompressed

[Tom Finegan, 2012/08/10 17:13:06]

Done.

+   * media to the user agent via the <code>PPB_ContentDecryptor_Private</code>
+   * interface.

[xhwang, 2012/08/10 16:41:30]

Should we mention to return the data via DeliverFrame() if it's video and via
DeliverSamples() if it's audio?

[Tom Finegan, 2012/08/10 17:13:06]

Done.

+   *
+   * @param[in] resource A <code>PP_Resource</code> corresponding to a
+   * <code>PPB_Buffer_Dev</code> resource that contains an encrypted data
+   * block.
+   *
+   * @param[in] request_id A value used by the user agent to associate data
+   * returned via the <code>PPB_ContentDecryptor_Private</code> interface with
+   * decryption method calls.
+   */
+  PP_Bool DecryptAndDecode(
+      [in] PP_Instance instance,
+      [in] PP_Resource encrypted_block,
+      [in] uint64_t request_id);
+};