Add unittests target to the binary distribution (issue #1632)

- Move all tests from the top-level directory to tests/.
- Move files shared by cefclient and unittests to tests/shared/.
- Add a fused (single header/source file) version of gtest in
  tests/gtest/ with associated CMake configuration.
- Test-only headers are now exposed in include/test/. Unit test
  targets must define UNIT_TEST in order to access them.
- Replace usage of USING_CEF_SHARED with WRAPPING_CEF_SHARED for
  clarity (only the libcef_dll_wrapper target should define it).
- Remove the RENAME_DIRECTORY CMake macro which is no longer used.
- Remove C++11 usage from unittests sources for compatibility with
  the binary distribution configuration.
- Windows: Fix build errors due to chrome_elf.dll and imm32.lib
  missing from the CMake configuration.

tests/shared/browser/util_win.h

@@ -0,0 +1,41 @@
+// Copyright (c) 2015 The Chromium Embedded Framework 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 CEF_TESTS_SHARED_BROWSER_UTIL_WIN_H_
+#define CEF_TESTS_SHARED_BROWSER_UTIL_WIN_H_
+#pragma once
+
+#include <windows.h>
+#include <string>
+
+#include "include/internal/cef_types_wrappers.h"
+
+namespace client {
+
+// Set the window's user data pointer.
+void SetUserDataPtr(HWND hWnd, void* ptr);
+
+// Return the window's user data pointer.
+template <typename T>
+T GetUserDataPtr(HWND hWnd) {
+  return reinterpret_cast<T>(GetWindowLongPtr(hWnd, GWLP_USERDATA));
+}
+
+// Set the window's window procedure pointer and return the old value.
+WNDPROC SetWndProcPtr(HWND hWnd, WNDPROC wndProc);
+
+// Return the resource string with the specified id.
+std::wstring GetResourceString(UINT id);
+
+int GetCefMouseModifiers(WPARAM wparam);
+int GetCefKeyboardModifiers(WPARAM wparam, LPARAM lparam);
+bool IsKeyDown(WPARAM wparam);
+
+// Returns the device scale factor. For example, 200% display scaling will
+// return 2.0.
+float GetDeviceScaleFactor();
+
+}  // namespace client
+
+#endif  // CEF_TESTS_SHARED_BROWSER_UTIL_WIN_H_