[Lockscreen Media Controls] Change container corner radius from 8px to 16px.

Bug: 1008186
Change-Id: I34db88b3c3e70c3227ab552c83ec2a0bdb2d3de3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1825864Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Jazz Xu <jazzhsu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#700019}

ash/login/ui/lock_screen_media_controls_view.cc

@@ -49,7 +49,7 @@ constexpr size_t kMaxActions = 5;
 
 // Dimensions.
 constexpr gfx::Insets kMediaControlsInsets = gfx::Insets(15, 15, 15, 15);
-constexpr int kMediaControlsCornerRadius = 8;
+constexpr int kMediaControlsCornerRadius = 16;
 constexpr int kMinimumIconSize = 16;
 constexpr int kDesiredIconSize = 20;
 constexpr int kIconSize = 20;