[cocoa] increase tab strip contrast in "Increase Contrast" mode

chrome/browser/themes/theme_service_mac.mm

Index: chrome/browser/themes/theme_service_mac.mm
diff --git a/chrome/browser/themes/theme_service_mac.mm b/chrome/browser/themes/theme_service_mac.mm
index a5654b94eff35a438fc1f8dfdb8cf49d10a3d705..8b89f8073d63d9965024a32cc3ecc8139e160280 100644
--- a/chrome/browser/themes/theme_service_mac.mm
+++ b/chrome/browser/themes/theme_service_mac.mm
@@ -7,6 +7,7 @@
 #import <Cocoa/Cocoa.h>
 
 #include "base/logging.h"
+#include "base/mac/mac_util.h"
 #include "chrome/browser/themes/browser_theme_pack.h"
 #include "chrome/browser/themes/theme_properties.h"
 #include "grit/theme_resources.h"
@@ -17,6 +18,12 @@
 #include "ui/gfx/color_utils.h"
 #include "ui/gfx/image/image.h"
 
+@interface NSWorkspace (Redeclarations)
+
+@property(readonly) BOOL accessibilityDisplayShouldIncreaseContrast;
+
+@end
+
 NSString* const kBrowserThemeDidChangeNotification =
     @"BrowserThemeDidChangeNotification";
 
@@ -405,3 +412,10 @@ NSColor* ThemeService::BrowserThemeProvider::GetNSColorTint(int id) const {
 NSGradient* ThemeService::BrowserThemeProvider::GetNSGradient(int id) const {
   return theme_service_.GetNSGradient(id);
 }
+
+bool ThemeService::BrowserThemeProvider::ShouldIncreaseContrast() const {
+  NSWorkspace* workspace = [NSWorkspace sharedWorkspace];
+  if (base::mac::IsOSYosemiteOrLater())

[Mark Mentovai, 2016/06/21 19:58:54]

Wouldn’t our usual style be to use -respondsToSelector instead of this?

[Elly Fong-Jones, 2016/06/21 20:25:36]

Done.

+    return workspace.accessibilityDisplayShouldIncreaseContrast == YES;
+  return false;
+}