ozone/wayland: Convert SkPath to DIPs before converted to rectangles

SkPath from |PlatformWindowDelegate::GetWindowMaskForWindowShape|
needs to be transformed in DIPs by the given |buffer_scale_|
before converted to rectangles.

TEST: test with --force-device-scale-factor
Bug: 1126828
Change-Id: I268e7266ba9131cf8eba481b1c30b93d2f1c3788
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2637098Reviewed-by: Nick Yamane <nickdiego@igalia.com>
Commit-Queue: MINJU KIM <mkim@igalia.com>
Cr-Commit-Position: refs/heads/master@{#845961}

ui/ozone/platform/wayland/common/wayland_util.cc

@@ -11,6 +11,7 @@
 #include "third_party/skia/include/core/SkRegion.h"
 #include "ui/base/hit_test.h"
 #include "ui/gfx/skia_util.h"
+#include "ui/gfx/transform.h"
 #include "ui/ozone/platform/wayland/host/wayland_connection.h"
 #include "ui/ozone/platform/wayland/host/wayland_shm_buffer.h"
 #include "ui/ozone/platform/wayland/host/wayland_surface.h"
@@ -292,4 +293,13 @@ std::vector<gfx::Rect> CreateRectsFromSkPath(const SkPath& path) {
   return rects;
 }
 
+SkPath ConvertPathToDIP(const SkPath& path_in_pixels, const int32_t scale) {
+  SkScalar sk_scale = SkFloatToScalar(1.0f / scale);
+  gfx::Transform transform;
+  transform.Scale(sk_scale, sk_scale);
+  SkPath path_in_dips;
+  path_in_pixels.transform(SkMatrix(transform.matrix()), &path_in_dips);
+  return path_in_dips;
+}
+
 }  // namespace wl

ui/ozone/platform/wayland/common/wayland_util.h

@@ -91,6 +91,9 @@ gfx::Rect TranslateWindowBoundsToParentDIP(ui::WaylandWindow* window,
 // Returns rectangles dictated by SkPath.
 std::vector<gfx::Rect> CreateRectsFromSkPath(const SkPath& path);
 
+// Returns converted SkPath in DIPs from the one in pixels.
+SkPath ConvertPathToDIP(const SkPath& path_in_pixels, const int32_t scale);
+
 }  // namespace wl
 
 #endif  // UI_OZONE_PLATFORM_WAYLAND_COMMON_WAYLAND_UTIL_H_

ui/ozone/platform/wayland/host/wayland_surface.cc

@@ -225,10 +225,11 @@ wl::Object<wl_region> WaylandSurface::CreateAndAddRegion(
                   region_dip.width(), region_dip.height());
   };
 
-  if (root_window_->GetWindowShape().has_value()) {
-    std::vector<gfx::Rect> rectangles = root_window_->GetWindowShape().value();
-    for (const auto& rect : rectangles)
-      add_region(rect);
+  auto window_shape_in_dips = root_window_->GetWindowShape();
+  if (window_shape_in_dips.has_value()) {
+    for (const auto& rect : window_shape_in_dips.value())
+      wl_region_add(region.get(), rect.x(), rect.y(), rect.width(),
+                    rect.height());
   } else {
     add_region(region_px);
   }

ui/ozone/platform/wayland/host/wayland_toplevel_window.cc

@@ -231,7 +231,7 @@ bool WaylandToplevelWindow::ShouldUseNativeFrame() const {
 
 base::Optional<std::vector<gfx::Rect>> WaylandToplevelWindow::GetWindowShape()
     const {
-  return window_shape_;
+  return window_shape_in_dips_;
 }
 
 void WaylandToplevelWindow::HandleSurfaceConfigure(int32_t width,
@@ -438,15 +438,18 @@ void WaylandToplevelWindow::UpdateWindowMask() {
 }
 
 void WaylandToplevelWindow::UpdateWindowShape() {
-  // Create |window_shape_| using the window mask of PlatformWindowDelegate
-  // otherwise resets it.
-  base::Optional<SkPath> window_mask = delegate()->GetWindowMaskForWindowShape(
+  // Create |window_shape_in_dips_| using the window mask of
+  // PlatformWindowDelegate otherwise resets it.
+  base::Optional<SkPath> window_mask_in_pixels =
+      delegate()->GetWindowMaskForWindowShape(
           gfx::Size(GetBounds().width(), GetBounds().height()));
-  if (window_mask.has_value()) {
-    window_shape_ = wl::CreateRectsFromSkPath(window_mask.value());
-  } else {
-    window_shape_.reset();
+  if (!window_mask_in_pixels.has_value()) {
+    window_shape_in_dips_.reset();
+    return;
   }
+  SkPath window_mask_in_dips =
+      wl::ConvertPathToDIP(window_mask_in_pixels.value(), buffer_scale());
+  window_shape_in_dips_ = wl::CreateRectsFromSkPath(window_mask_in_dips);
 }
 
 }  // namespace ui

ui/ozone/platform/wayland/host/wayland_toplevel_window.h

@@ -150,7 +150,7 @@ class WaylandToplevelWindow : public WaylandWindow,
   // e.g. lacros-taskmanager.
   bool use_native_frame_ = false;
 
-  base::Optional<std::vector<gfx::Rect>> window_shape_;
+  base::Optional<std::vector<gfx::Rect>> window_shape_in_dips_;
 };
 
 }  // namespace ui