[iOS][Alert][DarkMode] Use dynamic color for highlight state

Bug: 1001014
Change-Id: Ib07c934eccc2f89f89ca57f4fb35f05025006d32
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1787418
Auto-Submit: Javier Ernesto Flores Robles <javierrobles@chromium.org>
Reviewed-by: Mark Cogan <marq@chromium.org>
Commit-Queue: Javier Ernesto Flores Robles <javierrobles@chromium.org>
Cr-Commit-Position: refs/heads/master@{#695118}

ios/chrome/browser/ui/elements/BUILD.gn

@@ -28,6 +28,7 @@ source_set("elements") {
     "//ios/chrome/browser",
     "//ios/chrome/browser/ui/coordinators:chrome_coordinators",
     "//ios/chrome/browser/ui/util",
+    "//ios/chrome/common/colors",
   ]
 }
 

ios/chrome/browser/ui/elements/gray_highlight_button.mm

@@ -4,6 +4,8 @@
 
 #import "ios/chrome/browser/ui/elements/gray_highlight_button.h"
 
+#import "ios/chrome/common/colors/semantic_color_names.h"
+
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
@@ -13,7 +15,7 @@
 - (void)setHighlighted:(BOOL)highlighted {
   [super setHighlighted:highlighted];
   if (highlighted) {
-    self.backgroundColor = [UIColor colorWithWhite:235.0 / 255.0 alpha:1.0];
+    self.backgroundColor = [UIColor colorNamed:kTableViewRowHighlightColor];
   } else {
     self.backgroundColor = [UIColor clearColor];
   }