Add solid black background for arc immersive fullscreen.

components/exo/shell_surface.cc

Index: components/exo/shell_surface.cc
diff --git a/components/exo/shell_surface.cc b/components/exo/shell_surface.cc
index 10efe727153569f65763e70a2f63d143f92155cd..3d67b0ae94eb064ba286be950912abc3624bb2e9 100644
--- a/components/exo/shell_surface.cc
+++ b/components/exo/shell_surface.cc
@@ -1212,10 +1212,27 @@ void ShellSurface::UpdateShadow() {
   if (!widget_)
     return;
   aura::Window* window = widget_->GetNativeWindow();
+  ash::wm::WindowState* window_state = ash::wm::GetWindowState(window);
+
+  if (widget_->IsFullscreen() &&

[reveman, 2016/08/17 13:50:36]

why do we need to do this here instead of just adding this bounds logic to the
existing code for showing the shadow underlay below? 

[oshima, 2016/08/17 15:16:12]

We want to show this for all immersive fullscreen even if no shadow is
requested, so I put here to be safe side. There may not be such app, so I can
move it if you prefer. let me know.

[reveman, 2016/08/17 15:54:50]

Yes, Id prefer if you moved it and limited this to surfaces that have a shadow
set.

+      window_state->allow_set_bounds_in_maximized()) {
+    if (window->layer()->transform().IsIdentity()) {
+      wm::SetShadowType(window, wm::SHADOW_TYPE_NONE);
+      gfx::Point origin;
+      origin -= window->bounds().origin().OffsetFromOrigin();
+      gfx::Rect bounds(origin, window->parent()->bounds().size());
+      ShowShadowUnderlay(bounds, 1.f);
+    } else if (shadow_underlay_) {
+      shadow_underlay_->Hide();

[reveman, 2016/08/17 13:50:36]

why do we need to unconditionally hide the underlay just because the window is
transformed? shouldn't the existing shadow underlay logic be used in this case? 

[oshima, 2016/08/17 15:16:12]

Yes, you're right. Removed.

+    }
+    return;
+  }
+
   if (shadow_content_bounds_.IsEmpty()) {
     wm::SetShadowType(window, wm::SHADOW_TYPE_NONE);
     if (shadow_underlay_)
       shadow_underlay_->Hide();
+
   } else {
     wm::SetShadowType(window, wm::SHADOW_TYPE_RECTANGULAR);
 
@@ -1227,30 +1244,12 @@ void ShellSurface::UpdateShadow() {
     gfx::Rect shadow_bounds(shadow_origin, shadow_content_bounds_.size());
 
     // Always create and show the underlay, even in maximized/fullscreen.
-    if (!shadow_underlay_) {
-      shadow_underlay_ = new aura::Window(nullptr);
-      DCHECK(shadow_underlay_->owned_by_parent());
-      shadow_underlay_->set_ignore_events(true);
-      // Ensure the background area inside the shadow is solid black.
-      // Clients that provide translucent contents should not be using
-      // rectangular shadows as this method requires opaque contents to
-      // cast a shadow that represent it correctly.
-      shadow_underlay_->Init(ui::LAYER_SOLID_COLOR);
-      shadow_underlay_->layer()->SetColor(SK_ColorBLACK);
-      DCHECK(shadow_underlay_->layer()->fills_bounds_opaquely());
-      window->AddChild(shadow_underlay_);
-      window->StackChildAtBottom(shadow_underlay_);
-    }
-    shadow_underlay_->layer()->SetOpacity(
-        rectangular_shadow_background_opacity_);
-    shadow_underlay_->SetBounds(shadow_bounds);
-    shadow_underlay_->Show();
+    ShowShadowUnderlay(shadow_bounds, rectangular_shadow_background_opacity_);
 
     wm::Shadow* shadow = wm::ShadowController::GetShadowForWindow(window);
     // Maximized/Fullscreen window does not create a shadow.
     if (!shadow)
       return;
-
     if (!shadow_overlay_) {
       shadow_overlay_ = new aura::Window(nullptr);
       DCHECK(shadow_overlay_->owned_by_parent());
@@ -1265,4 +1264,25 @@ void ShellSurface::UpdateShadow() {
   }
 }
 
+void ShellSurface::ShowShadowUnderlay(const gfx::Rect& bounds, float opacity) {
+  if (!shadow_underlay_) {
+    aura::Window* window = widget_->GetNativeWindow();
+    shadow_underlay_ = new aura::Window(nullptr);
+    DCHECK(shadow_underlay_->owned_by_parent());
+    shadow_underlay_->set_ignore_events(true);
+    // Ensure the background area inside the shadow is solid black.
+    // Clients that provide translucent contents should not be using
+    // rectangular shadows as this method requires opaque contents to
+    // cast a shadow that represent it correctly.
+    shadow_underlay_->Init(ui::LAYER_SOLID_COLOR);
+    shadow_underlay_->layer()->SetColor(SK_ColorBLACK);
+    DCHECK(shadow_underlay_->layer()->fills_bounds_opaquely());
+    window->AddChild(shadow_underlay_);
+    window->StackChildAtBottom(shadow_underlay_);
+  }
+  shadow_underlay_->SetBounds(bounds);
+  shadow_underlay_->layer()->SetOpacity(opacity);
+  shadow_underlay_->Show();
+}
+
 }  // namespace exo