From 78e189b54ab07cb6f2dcb2d14ce321cdfe226c68 Mon Sep 17 00:00:00 2001
From: trav90 <travawine@protonmail.ch>
Date: Thu, 16 Mar 2017 03:15:49 -0500
Subject: [PATCH] Do tail dispatch automatically

---
 dom/media/AbstractThread.cpp |  7 ++++++-
 dom/media/AbstractThread.h   |  8 --------
 dom/media/MediaTaskQueue.cpp | 14 ++++++++++----
 dom/media/MediaTaskQueue.h   |  3 ++-
 4 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/dom/media/AbstractThread.cpp b/dom/media/AbstractThread.cpp
index 9be70c1ffa..9d9c60c7cc 100644
--- a/dom/media/AbstractThread.cpp
+++ b/dom/media/AbstractThread.cpp
@@ -30,8 +30,13 @@ public:
                         DispatchFailureHandling aFailureHandling = AssertDispatchSuccess,
                         DispatchReason aReason = NormalDispatch) override
   {
-    MOZ_ASSERT_IF(aReason != TailDispatch, !CurrentThreadRequiresTailDispatch());
     nsCOMPtr<nsIRunnable> r = aRunnable;
+    AbstractThread* currentThread;
+    if (aReason != TailDispatch && (currentThread = GetCurrent()) && currentThread->RequiresTailDispatch()) {
+      currentThread->TailDispatcher().AddTask(this, r.forget(), aFailureHandling);
+      return;
+    }
+
     nsresult rv = mTarget->Dispatch(r, NS_DISPATCH_NORMAL);
     MOZ_DIAGNOSTIC_ASSERT(aFailureHandling == DontAssertDispatchSuccess || NS_SUCCEEDED(rv));
     unused << rv;
diff --git a/dom/media/AbstractThread.h b/dom/media/AbstractThread.h
index 95155b39c9..7fd4b8377e 100644
--- a/dom/media/AbstractThread.h
+++ b/dom/media/AbstractThread.h
@@ -80,14 +80,6 @@ public:
   // Must be called exactly once during startup.
   static void InitStatics();
 
-  // Returns true if the currently-running thread is an AbstractThread that
-  // requires tail dispatch.
-  static bool CurrentThreadRequiresTailDispatch()
-  {
-    AbstractThread* current = GetCurrent();
-    return current && current->RequiresTailDispatch();
-  }
-
 protected:
   virtual ~AbstractThread() {}
   static ThreadLocal<AbstractThread*> sCurrentThreadTLS;
diff --git a/dom/media/MediaTaskQueue.cpp b/dom/media/MediaTaskQueue.cpp
index 12391b3a19..f1e33d73e6 100644
--- a/dom/media/MediaTaskQueue.cpp
+++ b/dom/media/MediaTaskQueue.cpp
@@ -40,11 +40,17 @@ MediaTaskQueue::TailDispatcher()
 
 nsresult
 MediaTaskQueue::DispatchLocked(already_AddRefed<nsIRunnable> aRunnable,
-                               DispatchMode aMode, DispatchReason aReason)
+                               DispatchMode aMode, DispatchFailureHandling aFailureHandling,
+                               DispatchReason aReason)
 {
-  MOZ_ASSERT_IF(aReason != TailDispatch, !CurrentThreadRequiresTailDispatch());
-  mQueueMonitor.AssertCurrentThreadOwns();
   nsCOMPtr<nsIRunnable> r = aRunnable;
+  AbstractThread* currentThread;
+  if (aReason != TailDispatch && (currentThread = GetCurrent()) && currentThread->RequiresTailDispatch()) {
+    currentThread->TailDispatcher().AddTask(this, r.forget(), aFailureHandling);
+    return NS_OK;
+  }
+
+  mQueueMonitor.AssertCurrentThreadOwns();
   if (mIsFlushing && aMode == AbortIfFlushing) {
     return NS_ERROR_ABORT;
   }
@@ -161,7 +167,7 @@ FlushableMediaTaskQueue::FlushAndDispatch(TemporaryRef<nsIRunnable> aRunnable)
   AutoSetFlushing autoFlush(this);
   FlushLocked();
   nsCOMPtr<nsIRunnable> r = dont_AddRef(aRunnable.take());
-  nsresult rv = DispatchLocked(r.forget(), IgnoreFlushing);
+  nsresult rv = DispatchLocked(r.forget(), IgnoreFlushing, AssertDispatchSuccess);
   NS_ENSURE_SUCCESS(rv, rv);
   AwaitIdleLocked();
   return NS_OK;
diff --git a/dom/media/MediaTaskQueue.h b/dom/media/MediaTaskQueue.h
index 9c3d0d2210..aadcbad0f9 100644
--- a/dom/media/MediaTaskQueue.h
+++ b/dom/media/MediaTaskQueue.h
@@ -47,7 +47,7 @@ public:
                 DispatchReason aReason = NormalDispatch) override
   {
     MonitorAutoLock mon(mQueueMonitor);
-    nsresult rv = DispatchLocked(Move(aRunnable), AbortIfFlushing, aReason);
+    nsresult rv = DispatchLocked(Move(aRunnable), AbortIfFlushing, aFailureHandling, aReason);
     MOZ_DIAGNOSTIC_ASSERT(aFailureHandling == DontAssertDispatchSuccess || NS_SUCCEEDED(rv));
     unused << rv;
   }
@@ -100,6 +100,7 @@ protected:
   enum DispatchMode { AbortIfFlushing, IgnoreFlushing };
 
   nsresult DispatchLocked(already_AddRefed<nsIRunnable> aRunnable, DispatchMode aMode,
+                          DispatchFailureHandling aFailureHandling,
                           DispatchReason aReason = NormalDispatch);
 
   RefPtr<SharedThreadPool> mPool;