Implements core logic for Pixel Canvas

ui/compositor/paint_context.cc

Index: ui/compositor/paint_context.cc
diff --git a/ui/compositor/paint_context.cc b/ui/compositor/paint_context.cc
index b2b4fac54b39a4c19adb6b398cd1d3674d3a5e58..48e2e9d8f684440a72cb910557a3c2f6c482ae19 100644
--- a/ui/compositor/paint_context.cc
+++ b/ui/compositor/paint_context.cc
@@ -10,10 +10,14 @@ namespace ui {
 
 PaintContext::PaintContext(cc::DisplayItemList* list,
                            float device_scale_factor,
-                           const gfx::Rect& invalidation)
+                           const gfx::Rect& invalidation,
+                           bool is_pixel_canvas)
     : list_(list),
       device_scale_factor_(device_scale_factor),
-      invalidation_(invalidation) {
+      invalidation_(gfx::ScaleToRoundedRect(
+          invalidation,
+          is_pixel_canvas ? device_scale_factor_ : 1.f)),
+      is_pixel_canvas_(is_pixel_canvas) {
 #if DCHECK_IS_ON()
   root_visited_ = nullptr;
   inside_paint_recorder_ = false;
@@ -25,7 +29,8 @@ PaintContext::PaintContext(const PaintContext& other,
     : list_(other.list_),
       device_scale_factor_(other.device_scale_factor_),
       invalidation_(other.invalidation_),
-      offset_(other.offset_ + offset) {
+      offset_(other.offset_ + offset),
+      is_pixel_canvas_(other.is_pixel_canvas_) {
 #if DCHECK_IS_ON()
   root_visited_ = other.root_visited_;
   inside_paint_recorder_ = other.inside_paint_recorder_;
@@ -37,7 +42,8 @@ PaintContext::PaintContext(const PaintContext& other,
     : list_(other.list_),
       device_scale_factor_(other.device_scale_factor_),
       invalidation_(),
-      offset_(other.offset_) {
+      offset_(other.offset_),
+      is_pixel_canvas_(other.is_pixel_canvas_) {
 #if DCHECK_IS_ON()
   root_visited_ = other.root_visited_;
   inside_paint_recorder_ = other.inside_paint_recorder_;