gitmerge: Using enums for cmd line args
gitdiff: Using enums for cmd line args
crbuild: Added ASAN support
crbuild: Ability to debug layout test
crbuild: Nascent support for building via GN
crbuild: Sync'ed up ASAN args with ASAN server's config
crbuild: devchrome depends on chrome_sandbox
crbuild: devchrome/normal allows file access
using platform.system to check for Windows