Bug 1588241 - P1. Use move semantics with PrependEvent. r=mattwoodrow

PrepentEvent was already moving the argument passed by reference. This makes it clear that the object will be moved.

Differential Revision: https://phabricator.services.mozilla.com/D52260

--HG--
extra : moz-landing-system : lando

netwerk/ipc/ChannelEventQueue.cpp

@@ -75,7 +75,7 @@ void ChannelEventQueue::FlushQueue() {
       // Next event needs to run on another thread. Put it back to
       // the front of the queue can try resume on that thread.
       Suspend();
-      PrependEvent(event);
+      PrependEvent(std::move(event));
 
       needResumeOnOtherThread = true;
       {

netwerk/ipc/ChannelEventQueue.h

@@ -102,7 +102,7 @@ class ChannelEventQueue final {
                            bool aAssertionWhenNotQueued = false);
 
   // Append ChannelEvent in front of the event queue.
-  inline nsresult PrependEvent(UniquePtr<ChannelEvent>& aEvent);
+  inline nsresult PrependEvent(UniquePtr<ChannelEvent>&& aEvent);
   inline nsresult PrependEvents(nsTArray<UniquePtr<ChannelEvent>>& aEvents);
 
   // After StartForcedQueueing is called, RunOrEnqueue() will start enqueuing
@@ -231,7 +231,7 @@ inline void ChannelEventQueue::EndForcedQueueing() {
 }
 
 inline nsresult ChannelEventQueue::PrependEvent(
-    UniquePtr<ChannelEvent>& aEvent) {
+    UniquePtr<ChannelEvent>&& aEvent) {
   MutexAutoLock lock(mMutex);
 
   // Prepending event while no queue flush foreseen might cause the following

netwerk/protocol/http/HttpChannelChild.cpp

@@ -3777,8 +3777,7 @@ void HttpChannelChild::CancelOnMainThread(nsresult aRv) {
   // Cancel is expected to preempt any other channel events, thus we put this
   // event in the front of mEventQ to make sure nsIStreamListener not receiving
   // any ODA/OnStopRequest callbacks.
-  UniquePtr<ChannelEvent> cancelEvent = MakeUnique<CancelEvent>(this, aRv);
-  mEventQ->PrependEvent(cancelEvent);
+  mEventQ->PrependEvent(MakeUnique<CancelEvent>(this, aRv));
   mEventQ->Resume();
 }