Set opaque region in ash frame

Bug: None
Change-Id: I8c19dce72cc631336002c5c979748ed78772046e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1948512Reviewed-by: Alexander Alekseev <alemate@chromium.org>
Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#721248}

ash/frame/non_client_frame_view_ash.cc

@@ -231,9 +231,14 @@ NonClientFrameViewAsh::NonClientFrameViewAsh(views::Widget* frame)
   }
 
   frame_window->SetProperty(kNonClientFrameViewAshKey, this);
+  frame_window->AddObserver(this);
 }
 
-NonClientFrameViewAsh::~NonClientFrameViewAsh() = default;
+NonClientFrameViewAsh::~NonClientFrameViewAsh() {
+  aura::Window* frame_window = frame_->GetNativeWindow();
+  if (frame_window && frame_window->HasObserver(this))
+    frame_window->RemoveObserver(this);
+}
 
 // static
 NonClientFrameViewAsh* NonClientFrameViewAsh::Get(aura::Window* window) {
@@ -362,6 +367,20 @@ void NonClientFrameViewAsh::SetVisible(bool visible) {
   InvalidateLayout();
 }
 
+void NonClientFrameViewAsh::OnWindowBoundsChanged(
+    aura::Window* window,
+    const gfx::Rect& old_bounds,
+    const gfx::Rect& new_bounds,
+    ui::PropertyChangeReason reason) {
+  if (window->transparent())
+    window->SetOpaqueRegionsForOcclusion({gfx::Rect(new_bounds.size())});
+}
+
+void NonClientFrameViewAsh::OnWindowDestroying(aura::Window* window) {
+  DCHECK_EQ(window, frame_->GetNativeWindow());
+  window->RemoveObserver(this);
+}
+
 void NonClientFrameViewAsh::SetShouldPaintHeader(bool paint) {
   header_view_->SetShouldPaintHeader(paint);
 }

ash/frame/non_client_frame_view_ash.h

@@ -14,6 +14,7 @@
 #include "base/memory/weak_ptr.h"
 #include "base/optional.h"
 #include "third_party/skia/include/core/SkColor.h"
+#include "ui/aura/window_observer.h"
 #include "ui/views/window/non_client_view.h"
 
 namespace views {
@@ -32,7 +33,8 @@ class NonClientFrameViewAshImmersiveHelper;
 // The window header overlay slides onscreen when the user hovers the mouse at
 // the top of the screen. See also views::CustomFrameView and
 // BrowserNonClientFrameViewAsh.
-class ASH_EXPORT NonClientFrameViewAsh : public views::NonClientFrameView {
+class ASH_EXPORT NonClientFrameViewAsh : public views::NonClientFrameView,
+                                         public aura::WindowObserver {
  public:
   // Internal class name.
   static const char kViewClassName[];
@@ -87,6 +89,13 @@ class ASH_EXPORT NonClientFrameViewAsh : public views::NonClientFrameView {
   gfx::Size GetMaximumSize() const override;
   void SetVisible(bool visible) override;
 
+  // aura::WindowObserver:
+  void OnWindowBoundsChanged(aura::Window* window,
+                             const gfx::Rect& old_bounds,
+                             const gfx::Rect& new_bounds,
+                             ui::PropertyChangeReason reason) override;
+  void OnWindowDestroying(aura::Window* window) override;
+
   // If |paint| is false, we should not paint the header. Used for overview mode
   // with OnOverviewModeStarting() and OnOverviewModeEnded() to hide/show the
   // header of v2 and ARC apps.

components/exo/shell_surface_base.cc

@@ -83,8 +83,7 @@ class ShellSurfaceWidget : public views::Widget {
   DISALLOW_COPY_AND_ASSIGN(ShellSurfaceWidget);
 };
 
-class CustomFrameView : public ash::NonClientFrameViewAsh,
-                        public aura::WindowObserver {
+class CustomFrameView : public ash::NonClientFrameViewAsh {
  public:
   using ShapeRects = std::vector<gfx::Rect>;
 
@@ -99,16 +98,9 @@ class CustomFrameView : public ash::NonClientFrameViewAsh,
     SetVisible(enabled);
     if (!enabled)
       NonClientFrameViewAsh::SetShouldPaintHeader(false);
-
-    frame()->GetNativeWindow()->AddObserver(this);
   }
 
-  ~CustomFrameView() override {
-    if (frame() && frame()->GetNativeWindow() &&
-        frame()->GetNativeWindow()->HasObserver(this)) {
-      frame()->GetNativeWindow()->RemoveObserver(this);
-    }
-  }
+  ~CustomFrameView() override = default;
 
   // Overridden from ash::NonClientFrameViewAsh:
   void SetShouldPaintHeader(bool paint) override {
@@ -118,11 +110,6 @@ class CustomFrameView : public ash::NonClientFrameViewAsh,
     }
   }
 
-  void OnWindowDestroying(aura::Window* window) override {
-    DCHECK_EQ(frame()->GetNativeWindow(), window);
-    window->RemoveObserver(this);
-  }
-
   // Overridden from views::NonClientFrameView:
   gfx::Rect GetBoundsForClientView() const override {
     if (GetVisible())