Fix include-what-you-use linter errors

  - components/viz/host/client_frame_sink_video_capturer.h
    :99   Add #include <memory> for unique_ptr<>
    :127  Add #include <string> for string

Bug: None
Test: No linter errors
Change-Id: I35a38c1e5e4b1c6f1ada7e0396d30504f0da35a3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2468959
Commit-Queue: Zentaro Kavanagh <zentaro@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Auto-Submit: Zentaro Kavanagh <zentaro@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#816776}

components/viz/host/client_frame_sink_video_capturer.h

@@ -5,6 +5,8 @@
 #ifndef COMPONENTS_VIZ_HOST_CLIENT_FRAME_SINK_VIDEO_CAPTURER_H_
 #define COMPONENTS_VIZ_HOST_CLIENT_FRAME_SINK_VIDEO_CAPTURER_H_
 
+#include <memory>
+#include <string>
 #include <vector>
 
 #include "base/callback.h"