ash: fix multiple stack-use-after-scope issues with GetPrimaryDisplay use.

ash/system/web_notification/ash_popup_alignment_delegate_unittest.cc

 // Copyright 2014 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/system/web_notification/ash_popup_alignment_delegate.h"
 
 #include <utility>
 #include <vector>
 
 #include "ash/common/shelf/wm_shelf.h"
@@ skipping 53 matching lines @@
     if (!delegate.get()) {
       alignment_delegate_.reset();
       return;
     }
     alignment_delegate_ = std::move(delegate);
     UpdateWorkArea(alignment_delegate_.get(),
                    display::Screen::GetScreen()->GetPrimaryDisplay());
   }
 
   Position GetPositionInDisplay(const gfx::Point& point) {
-    const gfx::Rect& work_area =
+    const gfx::Rect work_area =
         display::Screen::GetScreen()->GetPrimaryDisplay().work_area();
     const gfx::Point center_point = work_area.CenterPoint();
     if (work_area.x() > point.x() || work_area.y() > point.y() ||
         work_area.right() < point.x() || work_area.bottom() < point.y()) {
       return OUTSIDE;
     }
 
     if (center_point.x() < point.x())
       return (center_point.y() < point.y()) ? BOTTOM_RIGHT : TOP_RIGHT;
     else
@@ skipping 198 matching lines @@
   shelf->SetVirtualKeyboardBoundsForTesting(keyboard_bounds);
   int keyboard_baseline = alignment_delegate()->GetBaseLine();
   EXPECT_NE(baseline, keyboard_baseline);
   EXPECT_GT(keyboard_bounds.y(), keyboard_baseline);
 
   shelf->SetVirtualKeyboardBoundsForTesting(gfx::Rect());
   EXPECT_EQ(baseline, alignment_delegate()->GetBaseLine());
 }
 
 }  // namespace ash