allow non-downloading pipeline to play without download rate monitoring.

media/base/pipeline_impl.cc

 // Copyright (c) 2011 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.
 //
 // TODO(scherkus): clean up PipelineImpl... too many crazy function names,
 // potential deadlocks, etc...
 
 #include "media/base/pipeline_impl.h"
 
 #include <algorithm>
@@ skipping 1028 matching lines @@
     // We use audio stream to update the clock. So if there is such a stream,
     // we pause the clock until we receive a valid timestamp.
     waiting_for_clock_update_ = has_audio_;
     if (!waiting_for_clock_update_)
       clock_->Play();
 
     // Start monitoring rate of downloading.
     int bitrate = 0;
     if (demuxer_.get())
       bitrate = demuxer_->GetBitrate();
-    // Needs to be locked because most other calls to |download_rate_monitor_|
-    // occur on the renderer thread.
-    download_rate_monitor_.Start(
-        base::Bind(&PipelineImpl::OnCanPlayThrough, this), bitrate);
-    download_rate_monitor_.SetBufferedBytes(buffered_bytes_, base::Time::Now());
+
+    if (bitrate == 0) {
+      OnCanPlayThrough();
+    } else {
+      // Needs to be locked because most other calls to |download_rate_monitor_|
+      // occur on the renderer thread.
+      download_rate_monitor_.Start(
+          base::Bind(&PipelineImpl::OnCanPlayThrough, this), bitrate);
+      download_rate_monitor_.SetBufferedBytes(buffered_bytes_,
+                                              base::Time::Now());
+    }
 
     if (IsPipelineStopPending()) {
       // We had a pending stop request need to be honored right now.
       TearDownPipeline();
     }
   } else {
     NOTREACHED() << "Unexpected state: " << state_;
   }
 }
 
@@ skipping 367 matching lines @@
   message_loop_->PostTask(FROM_HERE,
       base::Bind(&PipelineImpl::NotifyCanPlayThrough, this));
 }
 
 void PipelineImpl::NotifyCanPlayThrough() {
   DCHECK_EQ(MessageLoop::current(), message_loop_);
   NotifyNetworkEventTask(CAN_PLAY_THROUGH);
 }
 
 }  // namespace media