fix shelf color with modal dialog.

ash/wm/focus_rules.cc

 // Copyright 2016 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/wm/focus_rules.h"
 
 #include "ash/public/cpp/shell_window_ids.h"
 #include "ash/shell.h"
 #include "ash/shell_delegate.h"
 #include "ash/wm/window_state.h"
 #include "ui/aura/window.h"
+#include "ui/wm/public/activation_delegate.h"
 
 namespace ash {
 
 bool IsToplevelWindow(aura::Window* window) {
   DCHECK(window);
   // The window must in a valid hierarchy.
   if (!window->GetRootWindow())
     return false;
 
   // The window must exist within a container that supports activation.
   // The window cannot be blocked by a modal transient.
   return IsActivatableShellWindowId(window->parent()->id());
 }
 
 bool IsWindowConsideredActivatable(aura::Window* window) {
   DCHECK(window);
   // Only toplevel windows can be activated.
   if (!IsToplevelWindow(window))
     return false;
 
-  // The window must be visible.
-  return IsWindowConsideredVisibleForActivation(window);
+  if (!IsWindowConsideredVisibleForActivation(window))
+    return false;
+
+  if (::wm::GetActivationDelegate(window) &&
+      !::wm::GetActivationDelegate(window)->ShouldActivate()) {
+    return false;
+  }
+
+  return window->CanFocus();
 }
 
 bool IsWindowConsideredVisibleForActivation(aura::Window* window) {
   DCHECK(window);
   // If the |window| doesn't belong to the current active user and also doesn't
   // show for the current active user, then it should not be activated.
   if (!Shell::Get()->shell_delegate()->CanShowWindowForUser(window))
     return false;
 
   if (window->IsVisible())
     return true;
 
   // Minimized windows are hidden in their minimized state, but they can always
   // be activated.
   if (wm::GetWindowState(window)->IsMinimized())
     return true;
 
   if (!window->TargetVisibility())
     return false;
 
   const int parent_shell_window_id = window->parent()->id();
   return parent_shell_window_id == kShellWindowId_DefaultContainer ||
          parent_shell_window_id == kShellWindowId_LockScreenContainer;
 }
 
 }  // namespace ash