[blink-scheduler] Don't create temporary scoped_refptr for map lookup

The HashTraits for scoped_refptr allow lookup by raw pointer value.

Bug: 1137931
Change-Id: I226e816e93ec631eb21ecb8ade66d7c0086ff3ae
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2533651Reviewed-by: Alexander Timin <altimin@chromium.org>
Commit-Queue: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#826822}

third_party/blink/renderer/platform/scheduler/main_thread/frame_scheduler_impl.cc

@@ -993,8 +993,8 @@ TaskQueue::QueuePriority FrameSchedulerImpl::ComputePriority(
   // Checks the task queue is associated with this frame scheduler.
   DCHECK_EQ(frame_scheduler, this);
 
-  auto queue_priority_pair = resource_loading_task_queue_priorities_.find(
-      base::WrapRefCounted(task_queue));
+  auto queue_priority_pair =
+      resource_loading_task_queue_priorities_.find(task_queue);
   if (queue_priority_pair != resource_loading_task_queue_priorities_.end())
     return queue_priority_pair->value;