Add content decryptor related structs and update PP{P|B}_ContentDecryptor_Private.

ppapi/api/private/ppp_content_decryptor_private.idl

Index: ppapi/api/private/ppp_content_decryptor_private.idl
diff --git a/ppapi/api/private/ppp_content_decryptor_private.idl b/ppapi/api/private/ppp_content_decryptor_private.idl
index bd663a4cf7ce5731e0f40afa9de323db18da883d..8423a4c32b157c70095e0972de990d790ff6e59f 100644
--- a/ppapi/api/private/ppp_content_decryptor_private.idl
+++ b/ppapi/api/private/ppp_content_decryptor_private.idl
@@ -85,14 +85,14 @@ interface PPP_ContentDecryptor_Private {
    * <code>PPB_Buffer_Dev</code> resource that contains an encrypted data
    * block.
    *
-   * @param[in] request_id A value used by the browser to associate data
-   * returned via the <code>PPB_ContentDecryptor_Private</code> interface with
-   * decryption method calls.
+   * @param[in] decrypt_config A <code>PP_DecryptConfig</code> that contains
+   * all auxiliary information needed for decryption of the
+   * <code>encrypted_block</code>.
    */
   PP_Bool Decrypt(
       [in] PP_Instance instance,
       [in] PP_Resource encrypted_block,
-      [in] int32_t request_id);
+      [in] PP_DecryptConfig decrypt_config);
 
   /**
    * Decrypts the block, decodes it, and returns the unencrypted uncompressed
@@ -107,12 +107,12 @@ interface PPP_ContentDecryptor_Private {
    * <code>PPB_Buffer_Dev</code> resource that contains an encrypted data
    * block.
    *
-   * @param[in] request_id A value used by the browser to associate data
-   * returned via the <code>PPB_ContentDecryptor_Private</code> interface with
-   * decryption method calls.
+   * @param[in] decrypt_config A <code>PP_DecryptConfig</code> that contains
+   * all auxiliary information needed for decryption of the
+   * <code>encrypted_block</code>.
    */
   PP_Bool DecryptAndDecode(
       [in] PP_Instance instance,
       [in] PP_Resource encrypted_block,
-      [in] int32_t request_id);
+      [in] PP_DecryptConfig decrypt_config);
 };