UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/51.0.2679.0 Chrome/51.0.2679.0 Safari/537.36

Steps to reproduce the problem:
Use the enable_hidpi flag to include hidpi resources (for example, enable_hidpi=true).

What is the expected behavior?

What went wrong?
A warning message is printed out:

ERROR at the command-line "--args":1:129: Build argument has no effect.
treat_warnings_as_errors=false use_sysroot=false enable_nacl=false linux_use_bundled_binutils=false use_gold=false enable_hidpi=true enable_widevine=true fieldtrial_testing_like_official_build=true target_cpu="x64" remove_webcore_debug_symbols=true is_clang=false is_component_build=true proprietary_codecs=true
                                                                                                                                ^---
The variable "enable_hidpi" was set as a build argument
but never appeared in a declare_args() block in any buildfile.

Did this work before? N/A 

Chrome version: 51.0.2679.0  Channel: n/a
OS Version: 
Flash Version: 

This flag worked when using gyp, but doesn't work under gn.