Update focus ring color for increased contrast option on Mac.

Per the comment in [1], this CL updates the focus ring color
when increased contrast is enabled on Mac to #101010.

[1] https://bugs.chromium.org/p/chromium/issues/detail?id=1054813#c22

Bug: 1054813
Change-Id: Iac10ec3a21bf920bd16744f7752d7a24a4aa1906
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2094345Reviewed-by: Kent Tamura <tkent@chromium.org>
Reviewed-by: Mason Freed <masonfreed@chromium.org>
Commit-Queue: Ionel Popescu <iopopesc@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#748483}

third_party/blink/renderer/core/layout/DEPS

 specific_include_rules = {
-  "layout_theme\.cc": [
+  "layout_theme\.cc|layout_theme_mac\.mm": [
     "+ui/native_theme/native_theme.h",
   ],
 }

third_party/blink/renderer/core/layout/layout_theme_mac.mm

@@ -45,6 +45,7 @@
 #import "third_party/blink/renderer/platform/runtime_enabled_features.h"
 #import "third_party/blink/renderer/platform/web_test_support.h"
 #include "ui/base/ui_base_features.h"
+#include "ui/native_theme/native_theme.h"
 
 // This is a view whose sole purpose is to tell AppKit that it's flipped.
 @interface BlinkFlippedControl : NSControl
@@ -348,6 +349,11 @@ Color LayoutThemeMacRefresh::FocusRingColor() const {
                                      : kDefaultFocusRingColor;
   }
 
+  if (ui::NativeTheme::GetInstanceForWeb()->UsesHighContrastColors()) {
+    // When high contrast is enabled, #101010 should be used.
+    return Color(0xFF101010);
+  }
+
   // TODO(crbug.com/929098) Need to pass an appropriate color scheme here.
   WebColorScheme color_scheme = ComputedStyle::InitialStyle().UsedColorScheme();
 

third_party/blink/tools/blinkpy/presubmit/audit_non_blink_usage.py

@@ -894,6 +894,7 @@ _CONFIG = [
     {
         'paths': [
             'third_party/blink/renderer/core/layout/layout_theme.cc',
+            'third_party/blink/renderer/core/layout/layout_theme_mac.mm',
             'third_party/blink/renderer/core/paint/fallback_theme.cc',
             'third_party/blink/renderer/core/paint/fallback_theme.h',
             'third_party/blink/renderer/core/paint/object_painter_base.cc',