Initial skeleton of high-contrast mode.

third_party/WebKit/Source/platform/graphics/GraphicsContext.h

 /*
  * Copyright (C) 2003, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2008-2009 Torch Mobile, Inc.
  * Copyright (C) 2013 Google 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.
@@ skipping 16 matching lines @@
 
 #ifndef GraphicsContext_h
 #define GraphicsContext_h
 
 #include <memory>
 #include "platform/PlatformExport.h"
 #include "platform/fonts/Font.h"
 #include "platform/graphics/DashArray.h"
 #include "platform/graphics/DrawLooperBuilder.h"
 #include "platform/graphics/GraphicsContextState.h"
+#include "platform/graphics/HighContrast.h"
 #include "platform/graphics/ImageOrientation.h"
 #include "platform/graphics/paint/PaintRecord.h"
 #include "platform/graphics/paint/PaintRecorder.h"
 #include "platform/graphics/skia/SkiaUtils.h"
 #include "platform/wtf/Allocator.h"
 #include "platform/wtf/Forward.h"
 #include "platform/wtf/Noncopyable.h"
 #include "third_party/skia/include/core/SkClipOp.h"
 #include "third_party/skia/include/core/SkImageFilter.h"
 #include "third_party/skia/include/core/SkMetaData.h"
@@ skipping 16 matching lines @@
   USING_FAST_MALLOC(GraphicsContext);
 
  public:
   enum DisabledMode {
     kNothingDisabled = 0,  // Run as normal.
     kFullyDisabled = 1     // Do absolutely minimal work to remove the cost of
                            // the context from performance tests.
   };
 
   explicit GraphicsContext(PaintController&,
+                           const HighContrastSettings* = nullptr,

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

Hmm. It seems that the constructor is not used at all after all most
of the time. Seems better to remove this and just have the setter.
Sorry for the churn, I was thinking it would be possible to 
have the high-contrast settings available at time of creation,
but since the creation is in platform/, that is not possible.

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

Done.

                            DisabledMode = kNothingDisabled,
                            SkMetaData* = 0);
 
   ~GraphicsContext();
 
   PaintCanvas* Canvas() { return canvas_; }
   const PaintCanvas* Canvas() const { return canvas_; }
 
   PaintController& GetPaintController() { return paint_controller_; }
 
   bool ContextDisabled() const { return disabled_state_; }
 
+  const HighContrastSettings& high_contrast_settings() {
+    return high_contrast_settings_;
+  }
+
   // ---------- State management methods -----------------
   void Save();
   void Restore();
 
 #if DCHECK_IS_ON()
   unsigned SaveCount() const;
 #endif
 
+  void SetHighContrast(const HighContrastSettings&);
+
   float StrokeThickness() const {
     return ImmutableState()->GetStrokeData().Thickness();
   }
   void SetStrokeThickness(float thickness) {
     MutableState()->SetStrokeThickness(thickness);
   }
 
   StrokeStyle GetStrokeStyle() const {
     return ImmutableState()->GetStrokeData().Style();
   }
@@ skipping 321 matching lines @@
       }
     }
   }
 
   void FillRectWithRoundedHole(const FloatRect&,
                                const FloatRoundedRect& rounded_hole_rect,
                                const Color&);
 
   const SkMetaData& MetaData() const { return meta_data_; }
 
+  void UpdateHighContrastFilterFromSettings();
+  Color ApplyHighContrastFilter(const Color& input) const;
+  PaintFlags ApplyHighContrastFilter(const PaintFlags* input) const;
+
   // null indicates painting is contextDisabled. Never delete this object.
   PaintCanvas* canvas_;
 
   PaintController& paint_controller_;
 
   // Paint states stack. The state controls the appearance of drawn content, so
   // this stack enables local drawing state changes with save()/restore() calls.
   // We do not delete from this stack to avoid memory churn.
   Vector<std::unique_ptr<GraphicsContextState>> paint_state_stack_;
 
@@ skipping 10 matching lines @@
 #if DCHECK_IS_ON()
   int layer_count_;
   bool disable_destruction_checks_;
   bool in_drawing_recorder_;
 #endif
 
   const DisabledMode disabled_state_;
 
   float device_scale_factor_;
 
+  HighContrastSettings high_contrast_settings_;
+  sk_sp<SkColorFilter> high_contrast_filter_;
+
   unsigned printing_ : 1;
   unsigned has_meta_data_ : 1;
 };
 
 }  // namespace blink
 
 #endif  // GraphicsContext_h