Merged: MediaCodecPlayer: prevent requesting data in wrong states

MediaCodecPlayer expects the demuxer response for each demuxer
data request. Currently it might happen that no response would
come after a data request, which might result in the player
lockup.

This situation might happen if the data request callback arrives
late at the Media thread, e.g. after the player started the Seek
sequence. In this case the data request could come after the
demuxer seek request which violates the demuxer contract.

This CL checks the decoder state before calling the data request
from demuxer.

BUG=557334

[email protected]

> Review URL: https://codereview.chromium.org/1455853002

> Cr-Commit-Position: refs/heads/master@{#360392}

Review URL: https://codereview.chromium.org/1457713003 .

Cr-Commit-Position: refs/branch-heads/2564@{crosswalk-project#49}
Cr-Branched-From: 1283eca-refs/heads/master@{#359700}

media/base/android/media_codec_decoder.cc

@@ -541,6 +541,19 @@ void MediaCodecDecoder::OnCodecError() {
 void MediaCodecDecoder::RequestData() {
   DCHECK(media_task_runner_->BelongsToCurrentThread());
 
+  // We request data only in kPrefetching, kPrerolling and kRunning states.
+  // For kPrerolling and kRunning this method is posted from Decoder thread,
+  // and by the time it arrives the player might be doing something else, e.g.
+  // seeking, in which case we should not request more data
+  switch (GetState()) {
+    case kPrefetching:
+    case kPrerolling:
+    case kRunning:
+      break;  // continue
+    default:
+      return;  // skip
+  }
+
   // Ensure one data request at a time.
   if (!is_data_request_in_progress_) {
     is_data_request_in_progress_ = true;