mash: Port sysui's WallpaperDelegateMus to mojo:ash.

ash/common/wallpaper/wallpaper_view.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/common/wallpaper/wallpaper_view.h"
 
 #include "ash/common/session/session_state_delegate.h"
 #include "ash/common/wallpaper/wallpaper_controller.h"
 #include "ash/common/wallpaper/wallpaper_delegate.h"
 #include "ash/common/wallpaper/wallpaper_widget_controller.h"
@@ skipping 26 matching lines @@
     view->SetPaintToLayer(true);
   }
 
   // Overrides views::View.
   void Layout() override {
     WmWindow* window = WmLookup::Get()->GetWindowForWidget(GetWidget());
     // Keep |this| at the bottom since there may be other windows on top of the
     // wallpaper view such as an overview mode shield.
     window->GetParent()->StackChildAtBottom(window);
     display::Display display = window->GetDisplayNearestWindow();
+
+    // TODO(mash): Mash returns a fake ManagedDisplayInfo. crbug.com/622480
+    float ui_scale = 1.f;
     display::ManagedDisplayInfo info =
         WmShell::Get()->GetDisplayInfo(display.id());
-    float ui_scale = info.GetEffectiveUIScale();
+    if (info.id() == display.id())
+      ui_scale = info.GetEffectiveUIScale();
+
     gfx::Size rounded_size =
         gfx::ScaleToFlooredSize(display.size(), 1.f / ui_scale);
     DCHECK_EQ(1, child_count());
     views::View* child = child_at(0);
     child->SetBounds(0, 0, rounded_size.width(), rounded_size.height());
     gfx::Transform transform;
     // Apply RTL transform explicitly becacuse Views layer code
     // doesn't handle RTL.  crbug.com/458753.
     transform.Translate(-child->GetMirroredX(), 0);
     transform.Scale(ui_scale, ui_scale);
@@ skipping 166 matching lines @@
     // Disable animation if transition to login screen from an empty background.
     wallpaper_window->SetVisibilityAnimationTransition(::wm::ANIMATE_NONE);
   }
 
   WmWindow* container = root_window->GetChildByShellWindowId(container_id);
   wallpaper_widget->SetBounds(container->GetBounds());
   return wallpaper_widget;
 }
 
 }  // namespace ash