Add support for loading extensions (issue #1947)

- Add CefRequestContext::LoadExtension, CefExtension, CefExtensionHandler and
  related methods/interfaces.
- Add chrome://extensions-support that lists supported Chrome APIs.
- Add CefBrowserHost::SetAutoResizeEnabled and CefDisplayHandler::OnAutoResize
  to support browser resize based on preferred web contents size.
- views: Add support for custom CefMenuButton popups.
- cefclient: Run with `--load-extension=set_page_color` command-line flag for
  an extension loading example. Add `--use-views` on Windows and Linux for an
  even better example.

tests/cefsimple/CMakeLists.txt.in

@@ -108,7 +108,6 @@ if(OS_MACOSX)
   add_dependencies(${CEF_TARGET} libcef_dll_wrapper "${CEF_HELPER_TARGET}")
   target_link_libraries(${CEF_TARGET} libcef_lib libcef_dll_wrapper ${CEF_STANDARD_LIBS})
   set_target_properties(${CEF_TARGET} PROPERTIES
-    RESOURCE "${CEFSIMPLE_RESOURCES_SRCS}"
     MACOSX_BUNDLE_INFO_PLIST ${CMAKE_CURRENT_SOURCE_DIR}/mac/Info.plist
     )
 
@@ -130,12 +129,12 @@ if(OS_MACOSX)
   # Fix the framework rpath in the main executable.
   FIX_MACOSX_MAIN_FRAMEWORK_RPATH(${CEF_TARGET})
 
-  if(NOT ${CMAKE_GENERATOR} STREQUAL "Xcode")
-    # Manually process and copy over resource files.
-    # The Xcode generator handles this via the set_target_properties RESOURCE directive.
-    set(PREFIXES "mac/")  # Remove these prefixes from input file paths.
-    COPY_MACOSX_RESOURCES("${CEFSIMPLE_RESOURCES_SRCS}" "${PREFIXES}" "${CEF_TARGET}" "${CMAKE_CURRENT_SOURCE_DIR}" "${CEF_APP}")
-  endif()
+  # Manually process and copy over resource files.
+  # The Xcode generator can support this via the set_target_properties RESOURCE
+  # directive but that doesn't properly handle nested resource directories.
+  # Remove these prefixes from input file paths.
+  set(PREFIXES "mac/")
+  COPY_MACOSX_RESOURCES("${CEFSIMPLE_RESOURCES_SRCS}" "${PREFIXES}" "${CEF_TARGET}" "${CMAKE_CURRENT_SOURCE_DIR}" "${CEF_APP}")
 endif()