Add GetDisplayWithDisplayId to display::Screen.

extensions/shell/browser/shell_screen_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 "extensions/shell/browser/shell_screen.h"
 
 #include <memory>
 
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/aura/test/aura_test_base.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_tree_host.h"
 #include "ui/display/display.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/size.h"
 
 namespace extensions {
 
 using ShellScreenTest = aura::test::AuraTestBase;
 
 // Basic sanity tests for ShellScreen.
 TEST_F(ShellScreenTest, ShellScreen) {
   ShellScreen screen(gfx::Size(640, 480));
 
   // There is only one display.
   EXPECT_EQ(1, screen.GetNumDisplays());
   EXPECT_EQ(1u, screen.GetAllDisplays().size());
   EXPECT_EQ(0, screen.GetAllDisplays()[0].id());
+  display::Display display;
+  bool has_display = screen.GetDisplayWithDisplayId(0, &display);
+  EXPECT_TRUE(has_display);
+  EXPECT_EQ(0, display.id());
   EXPECT_EQ(0, screen.GetPrimaryDisplay().id());
-  EXPECT_EQ("640x480", screen.GetPrimaryDisplay().size().ToString());
+  EXPECT_EQ("640x480", display.size().ToString());
 
   // Tests that reshaping the host window reshapes the display.
   // NOTE: AuraTestBase already has its own WindowTreeHost. This is creating a
   // second one.
   std::unique_ptr<aura::WindowTreeHost> host(
       screen.CreateHostForPrimaryDisplay());
   EXPECT_TRUE(host->window());
   host->window()->SetBounds(gfx::Rect(0, 0, 800, 600));
   EXPECT_EQ("800x600", screen.GetPrimaryDisplay().size().ToString());
 }
 
 }  // namespace extensions