Add LargeIconCache and LargeIconServiceFactory for iOS.

ios/chrome/browser/ui/uikit_ui_util.mm

Index: ios/chrome/browser/ui/uikit_ui_util.mm
diff --git a/ios/chrome/browser/ui/uikit_ui_util.mm b/ios/chrome/browser/ui/uikit_ui_util.mm
index 09fc391cac70987ba4fe0864617a7bc28e1d2a5f..86368ea1b4138f488cffffe9507f170fb4e3a63f 100644
--- a/ios/chrome/browser/ui/uikit_ui_util.mm
+++ b/ios/chrome/browser/ui/uikit_ui_util.mm
@@ -536,3 +536,10 @@ bool IsCompactTablet(id<UITraitEnvironment> environment) {
 bool IsCompactTablet() {
   return IsIPadIdiom() && IsCompact();
 }
+
+UIColor* ColorFromSkColor(SkColor color, CGFloat alpha) {
+  return [UIColor colorWithRed:SkColorGetR(color) / 255.0f
+                         green:SkColorGetG(color) / 255.0f
+                          blue:SkColorGetB(color) / 255.0f
+                         alpha:alpha];
+}