FileSystem.h includes wtf/Platform.h after using the PLATFORM macro. Depending on where FileSystem.h is included, PLATFORM might or might not be defined. In general though, wtf/Platform.h should be included at the very top of FileSystem.h.
Created attachment 33101 [details] patch
Comment on attachment 33101 [details] patch This is not correct. The implication of this change is that some .cpp file is not including config.h.
The problem is on the Chromium side.