[vr] Initialize some default colors

This CL sets default text colors

Bug: 845598
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_vr
Change-Id: Icede912c9fd697341d96a3f99425dc8cf5eb7497
Reviewed-on: https://chromium-review.googlesource.com/1069593Reviewed-by: Christopher Grant <cjgrant@chromium.org>
Commit-Queue: Christopher Grant <cjgrant@chromium.org>
Cr-Commit-Position: refs/heads/master@{#560805}

chrome/browser/vr/model/color_scheme.h

@@ -27,9 +27,9 @@ struct ButtonColors {
 struct TextSelectionColors {
   bool operator==(const TextSelectionColors& other) const;
   bool operator!=(const TextSelectionColors& other) const;
-  SkColor cursor;
-  SkColor background;
-  SkColor foreground;
+  SkColor cursor = SK_ColorBLACK;
+  SkColor background = SK_ColorBLACK;
+  SkColor foreground = SK_ColorBLACK;
 };
 
 struct ColorScheme {