cros: Remove some OS platform ifdefs from ash

ash/test/content/test_shell_content_state.h

 // Copyright 2015 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.
 
 #ifndef ASH_TEST_CONTENT_TEST_SHELL_CONTENT_STATE_H_
 #define ASH_TEST_CONTENT_TEST_SHELL_CONTENT_STATE_H_
 
 #include <memory>
 
 #include "ash/content/shell_content_state.h"
 #include "base/macros.h"
 
 namespace content {
 class BrowserContext;
 }
 
 namespace ash {
 namespace test {
 
 class TestShellContentState : public ShellContentState {
  public:
   TestShellContentState();
 
-#if defined(OS_CHROMEOS)
   content::ScreenOrientationDelegate* screen_orientation_delegate() {
     return &orientation_delegate_;
   }
-#endif
 
  private:
   ~TestShellContentState() override;
 
   // Overridden from ShellContentState:
   content::BrowserContext* GetActiveBrowserContext() override;
   content::BrowserContext* GetBrowserContextByIndex(UserIndex index) override;
   content::BrowserContext* GetBrowserContextForWindow(
       aura::Window* window) override;
   content::BrowserContext* GetUserPresentingBrowserContextForWindow(
       aura::Window* window) override;
 
   std::unique_ptr<content::BrowserContext> active_browser_context_;
 
   DISALLOW_COPY_AND_ASSIGN(TestShellContentState);
 };
 
 }  // namespace test
 }  // namespace ash
 
 #endif  // ASH_TEST_CONTENT_TEST_SHELL_CONTENT_STATE_H_