Missing including blink_strings.h in some files

Though below two files have been using IDS_FOO,
they have not included blink_strings.h files.

 - media_controls_touchless_overlay_element.cc
 - media_controls_touchless_time_display_element.cc

This CL includes blink_strings.h in those files.

Bug: 995644
Change-Id: I4e483aeaeaef5c93336c9f51c32087e9425d4841
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1830478Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Gyuyoung Kim <gyuyoung@igalia.com>
Cr-Commit-Position: refs/heads/master@{#700959}

third_party/blink/renderer/modules/media_controls/touchless/elements/media_controls_touchless_overlay_element.cc

@@ -4,6 +4,7 @@
 
 #include "third_party/blink/renderer/modules/media_controls/touchless/elements/media_controls_touchless_overlay_element.h"
 
+#include "third_party/blink/public/strings/grit/blink_strings.h"
 #include "third_party/blink/renderer/modules/media_controls/touchless/elements/media_controls_touchless_play_button_element.h"
 #include "third_party/blink/renderer/modules/media_controls/touchless/elements/media_controls_touchless_seek_button_element.h"
 #include "third_party/blink/renderer/modules/media_controls/touchless/elements/media_controls_touchless_volume_button_element.h"

third_party/blink/renderer/modules/media_controls/touchless/elements/media_controls_touchless_time_display_element.cc

@@ -4,6 +4,7 @@
 
 #include "third_party/blink/renderer/modules/media_controls/touchless/elements/media_controls_touchless_time_display_element.h"
 
+#include "third_party/blink/public/strings/grit/blink_strings.h"
 #include "third_party/blink/renderer/core/html/media/html_media_element.h"
 #include "third_party/blink/renderer/modules/media_controls/media_controls_shared_helper.h"
 #include "third_party/blink/renderer/modules/media_controls/touchless/media_controls_touchless_impl.h"