content: Rename RenderWidgetCompositor to LayerTreeView

In preparation for moving this class into the blink public platform
so blink can use it without going through WebLayerTreeView, rename
the class to mimic the interface it will replace in blink.

https://chromium-review.googlesource.com/c/chromium/src/+/1126490 did
this move and the rename together, but this CL splits out the rename.

[email protected]
TBR=piman

Bug: 838693
Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_slimming_paint_v2;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: I7e436862e5f5cbbf6d77c8eea1954fd31ecd3276
Reviewed-on: https://chromium-review.googlesource.com/1127447
Commit-Queue: danakj <[email protected]>
Reviewed-by: Kentaro Hara <[email protected]>
Cr-Commit-Position: refs/heads/master@{#572966}
diff --git a/content/renderer/render_thread_impl.h b/content/renderer/render_thread_impl.h
index 8cfd19d9..78326bc 100644
--- a/content/renderer/render_thread_impl.h
+++ b/content/renderer/render_thread_impl.h
@@ -283,12 +283,12 @@
   gpu::GpuMemoryBufferManager* GetGpuMemoryBufferManager();
 
   using LayerTreeFrameSinkCallback =
-      base::Callback<void(std::unique_ptr<cc::LayerTreeFrameSink>)>;
+      base::OnceCallback<void(std::unique_ptr<cc::LayerTreeFrameSink>)>;
   void RequestNewLayerTreeFrameSink(
       int routing_id,
       scoped_refptr<FrameSwapMessageQueue> frame_swap_message_queue,
       const GURL& url,
-      const LayerTreeFrameSinkCallback& callback,
+      LayerTreeFrameSinkCallback callback,
       mojom::RenderFrameMetadataObserverClientRequest
           render_frame_metadata_observer_client_request,
       mojom::RenderFrameMetadataObserverPtr render_frame_metadata_observer_ptr);