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

media/filters/chunk_demuxer.cc

 // 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.
 
 #include "media/filters/chunk_demuxer.h"
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
+#include "base/location.h"
 #include "base/logging.h"
-#include "base/message_loop.h"
+#include "base/message_loop_proxy.h"
 #include "base/string_util.h"
 #include "media/base/audio_decoder_config.h"
 #include "media/base/stream_parser_buffer.h"
 #include "media/base/video_decoder_config.h"
 #include "media/filters/chunk_demuxer_client.h"
 #if defined(GOOGLE_CHROME_BUILD) || defined(USE_PROPRIETARY_CODECS)
 #include "media/mp4/mp4_stream_parser.h"
 #endif
 #include "media/webm/webm_stream_parser.h"
 
@@ skipping 373 matching lines @@
     ChangeState_Locked(SHUTDOWN);
     std::swap(read_cbs_, read_cbs);
   }
 
   // Pass end of stream buffers to all callbacks to signal that no more data
   // will be sent.
   for (ReadCBQueue::iterator it = read_cbs.begin(); it != read_cbs.end(); ++it)
     it->Run(DemuxerStream::kOk, StreamParserBuffer::CreateEOSBuffer());
 }
 
-// Helper function that makes sure |read_cb| runs on |message_loop|.
-static void RunOnMessageLoop(const DemuxerStream::ReadCB& read_cb,
-                             MessageLoop* message_loop,
-                             DemuxerStream::Status status,
-                             const scoped_refptr<DecoderBuffer>& buffer) {
-  if (MessageLoop::current() != message_loop) {
-    message_loop->PostTask(FROM_HERE, base::Bind(
-        &RunOnMessageLoop, read_cb, message_loop, status, buffer));
+// Helper function that makes sure |read_cb| runs on |message_loop_proxy|.
+static void RunOnMessageLoop(
+    const DemuxerStream::ReadCB& read_cb,
+    const scoped_refptr<base::MessageLoopProxy>& message_loop_proxy,
+    DemuxerStream::Status status,
+    const scoped_refptr<DecoderBuffer>& buffer) {
+  if (!message_loop_proxy->BelongsToCurrentThread()) {
+    message_loop_proxy->PostTask(FROM_HERE, base::Bind(
+        &RunOnMessageLoop, read_cb, message_loop_proxy, status, buffer));
     return;
   }
 
   read_cb.Run(status, buffer);
 }
 
 // DemuxerStream methods.
 void ChunkDemuxerStream::Read(const ReadCB& read_cb) {
   DemuxerStream::Status status = kOk;
   scoped_refptr<StreamParserBuffer> buffer;
@@ skipping 29 matching lines @@
   state_ = state;
 }
 
 ChunkDemuxerStream::~ChunkDemuxerStream() {}
 
 void ChunkDemuxerStream::DeferRead_Locked(const ReadCB& read_cb) {
   lock_.AssertAcquired();
   // Wrap & store |read_cb| so that it will
   // get called on the current MessageLoop.
   read_cbs_.push_back(base::Bind(&RunOnMessageLoop, read_cb,
-                                 MessageLoop::current()));
+                                 base::MessageLoopProxy::current()));
 }
 
 void ChunkDemuxerStream::CreateReadDoneClosures_Locked(ClosureQueue* closures) {
   lock_.AssertAcquired();
 
   if (state_ != RETURNING_DATA_FOR_READS)
     return;
 
   DemuxerStream::Status status;
   scoped_refptr<StreamParserBuffer> buffer;
@@ skipping 589 matching lines @@
     video_->SetStartTime(start_time_);
     video_->Seek(start_time_);
   }
 
   // The demuxer is now initialized after the |start_timestamp_| was set.
   ChangeState_Locked(INITIALIZED);
   base::ResetAndReturn(&init_cb_).Run(PIPELINE_OK);
 }
 
 }  // namespace media