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/common/client_switches.h

@@ -0,0 +1,37 @@
+// Copyright (c) 2013 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.
+
+// Defines all of the command line switches used by cefclient.
+
+#ifndef CEF_TESTS_SHARED_SHARED_COMMON_SWITCHES_H_
+#define CEF_TESTS_SHARED_SHARED_COMMON_SWITCHES_H_
+#pragma once
+
+namespace client {
+namespace switches {
+
+extern const char kMultiThreadedMessageLoop[];
+extern const char kExternalMessagePump[];
+extern const char kCachePath[];
+extern const char kUrl[];
+extern const char kOffScreenRenderingEnabled[];
+extern const char kOffScreenFrameRate[];
+extern const char kTransparentPaintingEnabled[];
+extern const char kShowUpdateRect[];
+extern const char kMouseCursorChangeDisabled[];
+extern const char kRequestContextPerBrowser[];
+extern const char kRequestContextSharedCache[];
+extern const char kBackgroundColor[];
+extern const char kEnableGPU[];
+extern const char kFilterURL[];
+extern const char kUseViews[];
+extern const char kHideFrame[];
+extern const char kHideControls[];
+extern const char kWidevineCdmPath[];
+extern const char kSslClientCertificate[];
+
+}  // namespace switches
+}  // namespace client
+
+#endif  // CEF_TESTS_SHARED_SHARED_COMMON_SWITCHES_H_