[vr] Fix voice search button colors

Minor change to get the colors to match the spec.

Bug: None
Cq-Include-Trybots: luci.chromium.try:linux_optional_gpu_tests_rel;master.tryserver.chromium.android:android_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_vr;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
Change-Id: I9b16ca657ed0a4dcfd4fe28108997ef005e9e52f
Reviewed-on: https://chromium-review.googlesource.com/963687Reviewed-by: Michael Thiessen <mthiesse@chromium.org>
Commit-Queue: Ian Vollick <vollick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543288}

chrome/browser/vr/model/color_scheme.cc

@@ -130,8 +130,8 @@ void InitializeColorSchemes() {
   normal_scheme.omnibox_voice_search_button_colors.background =
       normal_scheme.omnibox_background;
   normal_scheme.omnibox_voice_search_button_colors.background_hover =
-      0xFFFAFAFA;
-  normal_scheme.omnibox_voice_search_button_colors.background_down = 0xFFFAFAFA;
+      0x14000000;
+  normal_scheme.omnibox_voice_search_button_colors.background_down = 0x14000000;
 
   normal_scheme.snackbar_foreground = 0xFFEEEEEE;
   normal_scheme.snackbar_background = 0xDD212121;