Initial skeleton of high-contrast mode.

third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp

 /*
  * Copyright (C) 2009, 2010, 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 144 matching lines @@
 }
 
 static inline bool IsAcceleratedContents(LayoutObject& layout_object) {
   return IsCompositedCanvas(layout_object) ||
          (layout_object.IsEmbeddedObject() &&
           ToLayoutEmbeddedObject(layout_object)
               .RequiresAcceleratedCompositing()) ||
          layout_object.IsVideo();
 }
 
+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;
+}
+
 CompositedLayerMapping::CompositedLayerMapping(PaintLayer& layer)
     : owning_layer_(layer),
       content_offset_in_compositing_layer_dirty_(false),
       pending_update_scope_(kGraphicsLayerUpdateNone),
       is_main_frame_layout_view_layer_(false),
       background_layer_paints_fixed_root_background_(false),
       scrolling_contents_are_empty_(false),
       background_paints_onto_scrolling_contents_layer_(false),
       background_paints_onto_graphics_layer_(false),
       draws_background_onto_content_layer_(false) {
@@ skipping 2907 matching lines @@
 #if DCHECK_IS_ON()
   if (!GetLayoutObject().View()->GetFrame() ||
       !GetLayoutObject().View()->GetFrame()->ShouldThrottleRendering())
     paint_info.paint_layer->GetLayoutObject().AssertSubtreeIsLaidOut();
 #endif
 
   float device_scale_factor = blink::DeviceScaleFactorDeprecated(
       paint_info.paint_layer->GetLayoutObject().GetFrame());
   context.SetDeviceScaleFactor(device_scale_factor);
 
+  HighContrastSettings high_contrast_settings =
+      InitHighContrastSettingsFromSettings(
+          GetLayoutObject().GetFrame()->GetSettings());

[chrishtr, 2017/06/05 16:35:18]

Can GetSettings ever return nullptr? If not then pass a const & and avoid
null-checks in InitHighContrastSettingsFromSettings.

[dmazzoni, 2017/06/06 05:23:24]

Looks like there's no way it can return nullptr, so I just got rid of the helper
and initialized it here. Seems simpler that way since it's only 3 lines of code.

+  context.SetHighContrast(high_contrast_settings);
+
   if (paint_info.paint_layer->GetCompositingState() !=
       kPaintsIntoGroupedBacking) {
     // FIXME: GraphicsLayers need a way to split for multicol.
     PaintLayerPaintingInfo painting_info(
         paint_info.paint_layer, LayoutRect(dirty_rect), kGlobalPaintNormalPhase,
         paint_info.paint_layer->SubpixelAccumulation());
     PaintLayerPainter(*paint_info.paint_layer)
         .PaintLayerContents(context, painting_info, paint_layer_flags);
 
     if (paint_info.paint_layer->ContainsDirtyOverlayScrollbars())
@@ skipping 561 matching lines @@
   } else if (graphics_layer == decoration_outline_layer_.get()) {
     name = "Decoration Layer";
   } else {
     NOTREACHED();
   }
 
   return name;
 }
 
 }  // namespace blink