Implements core logic for Pixel Canvas

ui/compositor/paint_recorder.cc

Index: ui/compositor/paint_recorder.cc
diff --git a/ui/compositor/paint_recorder.cc b/ui/compositor/paint_recorder.cc
index 8a8c4c28caf55c97e0c6cc0c0bc55e86f98430cc..e1cb2807176bf93e943b48423633af44ec44e014 100644
--- a/ui/compositor/paint_recorder.cc
+++ b/ui/compositor/paint_recorder.cc
@@ -32,16 +32,27 @@ PaintRecorder::PaintRecorder(const PaintContext& context,
   DCHECK(!context.inside_paint_recorder_);
   context.inside_paint_recorder_ = true;
 #endif
+  if (context_.IsPixelCanvas()) {
+    canvas()->Save();
+    canvas()->Scale(context.paint_recording_scale_x_,
+                    context.paint_recording_scale_y_);
+  }
 }
 
 PaintRecorder::PaintRecorder(const PaintContext& context,
                              const gfx::Size& recording_size)
-    : PaintRecorder(context, recording_size, nullptr) {}
+    : PaintRecorder(context,
+                    gfx::ScaleToRoundedSize(recording_size,
+                                            context.paint_recording_scale_x_,
+                                            context.paint_recording_scale_y_),
+                    nullptr) {}
 
 PaintRecorder::~PaintRecorder() {
 #if DCHECK_IS_ON()
   context_.inside_paint_recorder_ = false;
 #endif
+  if (context_.IsPixelCanvas())
+    canvas()->Restore();
   // If using cache, append what we've saved there to the PaintContext.
   // Otherwise, the content is already stored in the PaintContext, and we can
   // just close it.