Initial skeleton of high-contrast mode.

third_party/WebKit/Source/core/paint/PaintLayerPainter.cpp

Index: third_party/WebKit/Source/core/paint/PaintLayerPainter.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintLayerPainter.cpp b/third_party/WebKit/Source/core/paint/PaintLayerPainter.cpp
index 05fc565f04bfc5cc77cfeccef5166c84a748d180..3d47b2baf004e5a866f9abc911916bc5d05db7c3 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayerPainter.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayerPainter.cpp
@@ -5,6 +5,8 @@
 #include "core/paint/PaintLayerPainter.h"
 
 #include "core/frame/FrameView.h"
+#include "core/frame/LocalFrame.h"
+#include "core/frame/Settings.h"
 #include "core/layout/LayoutView.h"
 #include "core/paint/ClipPathClipper.h"
 #include "core/paint/FilterPainter.h"
@@ -29,6 +31,21 @@
 
 namespace blink {
 
+static HighContrastSettings InitHighContrastSettingsFromSettings(
+    Settings* settings) {
+  HighContrastSettings result;
+  if (settings) {
+    result.mode = settings->GetHighContrastMode();
+    result.grayscale = settings->GetHighContrastGrayscale();
+    result.contrast = settings->GetHighContrastContrast();
+  } else {
+    result.mode = HighContrastMode::kOff;
+    result.grayscale = false;
+    result.contrast = 0.0;
+  }
+  return result;
+}
+
 static inline bool ShouldSuppressPaintingLayer(const PaintLayer& layer) {
   // Avoid painting descendants of the root layer when stylesheets haven't
   // loaded. This avoids some FOUC.  It's ok not to draw, because later on, when
@@ -273,6 +290,13 @@ PaintResult PaintLayerPainter::PaintLayerContents(
   if (paint_layer_.GetLayoutObject().GetFrameView()->ShouldThrottleRendering())
     return result;
 
+  HighContrastSettings high_contrast_settings =
+      InitHighContrastSettingsFromSettings(paint_layer_.GetLayoutObject()
+                                               .GetFrameView()
+                                               ->GetFrame()
+                                               .GetSettings());
+  context.SetHighContrast(high_contrast_settings);
+
   Optional<ScopedPaintChunkProperties> scoped_paint_chunk_properties;
   if (RuntimeEnabledFeatures::slimmingPaintV2Enabled() &&
       RuntimeEnabledFeatures::rootLayerScrollingEnabled() &&