Initial skeleton of high-contrast mode.

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

Index: third_party/WebKit/Source/platform/graphics/GraphicsContext.h
diff --git a/third_party/WebKit/Source/platform/graphics/GraphicsContext.h b/third_party/WebKit/Source/platform/graphics/GraphicsContext.h
index a0cf6f35e5efda023d03f65bc894da2727b277a2..a4023859c594bcfbc9bac328012defd7505d7c1b 100644
--- a/third_party/WebKit/Source/platform/graphics/GraphicsContext.h
+++ b/third_party/WebKit/Source/platform/graphics/GraphicsContext.h
@@ -34,6 +34,7 @@
 #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"
@@ -70,6 +71,7 @@ class PLATFORM_EXPORT GraphicsContext {
   };
 
   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);
 
@@ -82,6 +84,10 @@ class PLATFORM_EXPORT GraphicsContext {
 
   bool ContextDisabled() const { return disabled_state_; }
 
+  const HighContrastSettings& high_contrast_settings() {
+    return high_contrast_settings_;
+  }
+
   // ---------- State management methods -----------------
   void Save();
   void Restore();
@@ -90,6 +96,8 @@ class PLATFORM_EXPORT GraphicsContext {
   unsigned SaveCount() const;
 #endif
 
+  void SetHighContrast(const HighContrastSettings&);
+
   float StrokeThickness() const {
     return ImmutableState()->GetStrokeData().Thickness();
   }
@@ -431,6 +439,10 @@ class PLATFORM_EXPORT GraphicsContext {
 
   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_;
 
@@ -461,6 +473,9 @@ class PLATFORM_EXPORT GraphicsContext {
 
   float device_scale_factor_;
 
+  HighContrastSettings high_contrast_settings_;
+  sk_sp<SkColorFilter> high_contrast_filter_;
+
   unsigned printing_ : 1;
   unsigned has_meta_data_ : 1;
 };