Fix presubmit warning in root_compositor_frame_sink_impl.h

std::vector<> is used, but not included, resulting in a presubmit
warning. This CL adds the include to fix the warning.

Change-Id: I40e7bcd24c15ddb885fd4d52dbab7122105b1531
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2324107Reviewed-by: Jonathan Ross <jonross@chromium.org>
Commit-Queue: Mario Bianucci <mabian@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#792574}

components/viz/service/frame_sinks/root_compositor_frame_sink_impl.h

@@ -6,6 +6,7 @@
 #define COMPONENTS_VIZ_SERVICE_FRAME_SINKS_ROOT_COMPOSITOR_FRAME_SINK_IMPL_H_
 
 #include <memory>
+#include <vector>
 
 #include "base/macros.h"
 #include "base/memory/read_only_shared_memory_region.h"