[Mac] Increase color contrast on Credit Card Autofill Touch Bar

Bug: 794067
Change-Id: Ie2abc3d1b6b139d026508fc7ed2b20e5e57efedc
Reviewed-on: https://chromium-review.googlesource.com/927451Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Commit-Queue: Sarah Chan <spqchan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#537920}

chrome/browser/ui/cocoa/autofill/credit_card_autofill_touch_bar_controller.mm

@@ -110,9 +110,9 @@ NSImage* GetCreditCardTouchBarImage(int iconId) {
 }
 
 - (NSColor*)touchBarSubtextColor {
-  return [NSColor colorWithCalibratedRed:180.0 / 255.0
-                                   green:180.0 / 255.0
-                                    blue:180.0 / 255.0
+  return [NSColor colorWithCalibratedRed:206.0 / 255.0
+                                   green:206.0 / 255.0
+                                    blue:206.0 / 255.0
                                    alpha:1.0];
 }