Implement "pinned" mode in ash.

ash/wm/workspace/workspace_layout_manager_unittest.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/wm/workspace/workspace_layout_manager.h"
 
 #include <string>
 #include <utility>
 
 #include "ash/aura/wm_window_aura.h"
@@ skipping 658 matching lines @@
   fullscreen_window->SetProperty(aura::client::kShowStateKey,
                                  ui::SHOW_STATE_NORMAL);
   EXPECT_TRUE(
       always_on_top_window1->GetProperty(aura::client::kAlwaysOnTopKey));
   EXPECT_TRUE(
       always_on_top_window2->GetProperty(aura::client::kAlwaysOnTopKey));
   EXPECT_EQ(nullptr, GetRootWindowController(fullscreen_window->GetRootWindow())
                          ->GetWindowForFullscreenMode());
 }
 
+// Similary, pinned window causes always_on_top_ windows to stack below.
+TEST_F(WorkspaceLayoutManagerSoloTest, PinnedSuspendsAlwaysOnTop) {
+  gfx::Rect bounds(100, 100, 200, 200);
+  std::unique_ptr<aura::Window> pinned_window(CreateTestWindow(bounds));
+  std::unique_ptr<aura::Window> always_on_top_window1(CreateTestWindow(bounds));
+  std::unique_ptr<aura::Window> always_on_top_window2(CreateTestWindow(bounds));
+  always_on_top_window1->SetProperty(aura::client::kAlwaysOnTopKey, true);
+  always_on_top_window2->SetProperty(aura::client::kAlwaysOnTopKey, true);
+
+  // Making a window pinned temporarily suspends always on top state.
+  wm::PinWindow(pinned_window.get());
+  EXPECT_FALSE(
+      always_on_top_window1->GetProperty(aura::client::kAlwaysOnTopKey));
+  EXPECT_FALSE(
+      always_on_top_window2->GetProperty(aura::client::kAlwaysOnTopKey));
+
+  // Making pinned window normal restores always on top windows.
+  WmWindowAura::Get(pinned_window.get())->GetWindowState()->Restore();
+  EXPECT_TRUE(
+      always_on_top_window1->GetProperty(aura::client::kAlwaysOnTopKey));
+  EXPECT_TRUE(
+      always_on_top_window2->GetProperty(aura::client::kAlwaysOnTopKey));
+}
+
 // Tests fullscreen window size during root window resize.
 TEST_F(WorkspaceLayoutManagerSoloTest, FullscreenRootWindowResize) {
   gfx::Rect bounds(100, 100, 200, 200);
   std::unique_ptr<aura::Window> window(CreateTestWindow(bounds));
   // Fullscreen window fills the whole display.
   window->SetProperty(aura::client::kShowStateKey, ui::SHOW_STATE_FULLSCREEN);
   EXPECT_EQ(display::Screen::GetScreen()
                 ->GetDisplayNearestWindow(window.get())
                 .bounds()
                 .ToString(),
@@ skipping 463 matching lines @@
   EXPECT_EQ(gfx::Rect(50,
                       keyboard_bounds.y() - keyboard_bounds.height()/2,
                       occluded_window_bounds.width(),
                       occluded_window_bounds.height()).ToString(),
             window->bounds().ToString());
   HideKeyboard();
   EXPECT_EQ(occluded_window_bounds.ToString(), window->bounds().ToString());
 }
 
 }  // namespace ash