corresponding change in CaptureVideoDecoder and RTCVideoDecoder due to pull model used in medi...

content/renderer/media/rtc_video_decoder.cc

Index: content/renderer/media/rtc_video_decoder.cc
===================================================================
--- content/renderer/media/rtc_video_decoder.cc	(revision 109978)
+++ content/renderer/media/rtc_video_decoder.cc	(working copy)
@@ -4,8 +4,6 @@
 
 #include "content/renderer/media/rtc_video_decoder.h"
 
-#include <deque>
-
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/message_loop.h"
@@ -87,6 +85,27 @@
   VideoDecoder::Pause(callback);
 }
 
+void RTCVideoDecoder::Flush(const base::Closure& callback) {
+  if (MessageLoop::current() != message_loop_) {
+    message_loop_->PostTask(FROM_HERE,
+                            base::Bind(&RTCVideoDecoder::Flush,
+                                       this, callback));
+    return;
+  }
+
+  DCHECK_EQ(MessageLoop::current(), message_loop_);
+
+  {
+    base::AutoLock auto_lock(lock_);
+    while (!read_cbs_.empty()) {
+      DeliverBlackFrame(read_cbs_.front());
+      read_cbs_.pop();
+    }
+  }
+
+  VideoDecoder::Flush(callback);
+}
+
 void RTCVideoDecoder::Stop(const base::Closure& callback) {
   if (MessageLoop::current() != message_loop_) {
     message_loop_->PostTask(FROM_HERE,
@@ -123,9 +142,13 @@
     return;
   }
   DCHECK_EQ(MessageLoop::current(), message_loop_);
+  CHECK(!callback.is_null());
+  if (state_ != kNormal) {
+    DeliverBlackFrame(callback);
+    return;
+  }
   base::AutoLock auto_lock(lock_);
-  CHECK(read_cb_.is_null());
-  read_cb_ = callback;
+  read_cbs_.push(callback);
 }
 
 const gfx::Size& RTCVideoDecoder::natural_size() {
@@ -141,6 +164,10 @@
   return true;
 }
 
+// TODO(wjia): this function can be split into two parts so that the |lock_|
+// can be removed.
+// First creates media::VideoFrame, then post a task onto |message_loop_|
+// to deliver that frame.
 bool RTCVideoDecoder::RenderFrame(const cricket::VideoFrame* frame) {
   // Called from libjingle thread.
   DCHECK(frame);
@@ -151,10 +178,11 @@
   ReadCB read_cb;
   {
     base::AutoLock auto_lock(lock_);
-    if (read_cb_.is_null()) {
+    if (read_cbs_.empty()) {
       return true;
     }
-    std::swap(read_cb, read_cb_);
+    read_cb = read_cbs_.front();
+    read_cbs_.pop();
   }
 
   // Always allocate a new frame.
@@ -180,3 +208,12 @@
   read_cb.Run(video_frame);
   return true;
 }
+
+void RTCVideoDecoder::DeliverBlackFrame(
+    const ReadCB& read_cb) {
+  CHECK(!read_cb.is_null());
+  scoped_refptr<media::VideoFrame> video_frame =
+      media::VideoFrame::CreateBlackFrame(visible_size_.width(),
+                                          visible_size_.height());
+  read_cb.Run(video_frame);
+}