Allowing C++14 in libyuv.

Bug: None
Change-Id: I2600e1012fa3fab5b8d2ad6e4af44dfa97e95ea4
Reviewed-on: https://chromium-review.googlesource.com/c/libyuv/libyuv/+/1789304Reviewed-by: Frank Barchard <fbarchard@chromium.org>
Commit-Queue: Mirko Bonadei <mbonadei@chromium.org>

.gn

@@ -31,12 +31,6 @@ exec_script_whitelist = build_dotfile_settings.exec_script_whitelist +
 default_args = {
   mac_sdk_min = "10.12"
 
-  # LibYUV does not want to switch to C++14 yet.
-  use_cxx11 = true
-
-  # LibYUV relies on Chromium's Android test infrastructure.
-  use_cxx11_on_android = false
-
   # https://bugs.chromium.org/p/libyuv/issues/detail?id=826
   ios_deployment_target = "10.0"
 }