Remove VideoDecoder::PrepareForShutdownHack() and friends.

content/renderer/media/rtc_video_decoder.cc

Index: content/renderer/media/rtc_video_decoder.cc
diff --git a/content/renderer/media/rtc_video_decoder.cc b/content/renderer/media/rtc_video_decoder.cc
index 810856706ba54ca2d3ba92ca46b38ba056cc53c8..d86a2ae10ebb8b9c5a2ecd8149a6a2c69cb2a540 100644
--- a/content/renderer/media/rtc_video_decoder.cc
+++ b/content/renderer/media/rtc_video_decoder.cc
@@ -34,7 +34,6 @@ RTCVideoDecoder::RTCVideoDecoder(base::TaskRunner* video_decoder_thread,
       visible_size_(640, 480),
       state_(kUnInitialized),
       got_first_frame_(false),
-      shutting_down_(false),
       video_track_(video_track) {
 }
 
@@ -68,12 +67,13 @@ void RTCVideoDecoder::Read(const ReadCB& read_cb) {
 
   base::AutoLock auto_lock(lock_);
   CHECK(read_cb_.is_null());
-  read_cb_ = read_cb;
 
-  if (shutting_down_) {
-    video_decoder_thread_->PostTask(FROM_HERE,
-        base::Bind(&RTCVideoDecoder::CancelPendingRead, this));
+  if (state_ == kStopped) {
+    read_cb.Run(kOk, NULL);
+    return;
   }
+
+  read_cb_ = read_cb;
 }
 
 void RTCVideoDecoder::Reset(const base::Closure& closure) {
@@ -99,18 +99,8 @@ void RTCVideoDecoder::Stop(const base::Closure& closure) {
   }
 
   state_ = kStopped;
-  closure.Run();
-}
-
-void RTCVideoDecoder::PrepareForShutdownHack() {
-  if (!video_decoder_thread_->RunsTasksOnCurrentThread()) {
-    video_decoder_thread_->PostTask(
-        FROM_HERE, base::Bind(&RTCVideoDecoder::PrepareForShutdownHack,
-                              this));
-    return;
-  }
-  shutting_down_ = true;
   CancelPendingRead();
+  closure.Run();
 }
 
 void RTCVideoDecoder::SetSize(int width, int height) {