Initial skeleton of high-contrast mode.

third_party/WebKit/Source/core/frame/Settings.json5

Index: third_party/WebKit/Source/core/frame/Settings.json5
diff --git a/third_party/WebKit/Source/core/frame/Settings.json5 b/third_party/WebKit/Source/core/frame/Settings.json5
index 84b492711ee8d6d63ea75f2bb147504cf877c21c..0731d5f055a5d4f09f5e6ffdaddebc23fddb26e3 100644
--- a/third_party/WebKit/Source/core/frame/Settings.json5
+++ b/third_party/WebKit/Source/core/frame/Settings.json5
@@ -924,5 +924,23 @@
       type: "AutoplayPolicy::Type",
       initial: "AutoplayPolicy::Type::kNoUserGestureRequired",
     },
+
+    //
+    // High contrast mode
+    //
+    {
+      name: "highContrastMode",
+      initial: "HighContrastMode::kOff",
+      type: "HighContrastMode",
+    },
+    {
+      name: "highContrastGrayscale",
+      initial: false,
+    },
+    {
+      name: "highContrastContrast",
+      initial: 0,
+      type: "double",
+    }
   ],
 }