Bug 1644009 - P7. Revert "Bug 1592488 - P4. Ensure an AbstractThread exists for the Compositor Thread." r=mattwoodrow

DirectTask dispatching will now be directly handled by nsThread.

Differential Revision: https://phabricator.services.mozilla.com/D79091

Author: Jean-Yves Avenard

gfx/layers/ipc/CompositorThread.cpp

@@ -34,9 +34,7 @@ CompositorThreadHolder* CompositorThreadHolder::GetSingleton() {
 }
 
 CompositorThreadHolder::CompositorThreadHolder()
-    : mCompositorThread(CreateCompositorThread()),
-      mCompositorAbstractThread(AbstractThread::CreateXPCOMThreadWrapper(
-          mCompositorThread, false /* aRequireTailDispatch */)) {
+    : mCompositorThread(CreateCompositorThread()) {
   MOZ_ASSERT(NS_IsMainThread());
 }
 

gfx/layers/ipc/CompositorThread.h

@@ -13,7 +13,6 @@ class nsISerialEventTarget;
 class nsIThread;
 
 namespace mozilla {
-class AbstractThread;
 namespace layers {
 
 class CompositorThreadHolder final {
@@ -48,8 +47,7 @@ class CompositorThreadHolder final {
  private:
   ~CompositorThreadHolder();
 
-  const nsCOMPtr<nsIThread> mCompositorThread;
-  const RefPtr<AbstractThread> mCompositorAbstractThread;
+  nsCOMPtr<nsIThread> mCompositorThread;
 
   static already_AddRefed<nsIThread> CreateCompositorThread();