gn: some vim support files

tools/gn/misc/vim/syntax/gn.vim

+" Copyright 2014 The Chromium Authors. All rights reserved.
+" Use of this source code is governed by a BSD-style license that can be
+" found in the LICENSE file.
+"
+" gn.vim: Vim syntax file for GN.
+"
+" Quit when a (custom) syntax file was already loaded
+"if exists("b:current_syntax")
+  "finish
+"endif
+
+syn case match
+
+" Keywords within functions
+syn keyword     gnConditional       if else
+hi def link     gnConditional       Conditional
+
+" Predefined variables
+syn keyword     gnPredefVar build_cpu_arch build_os cpu_arch current_toolchain
+syn keyword     gnPredefVar default_toolchain os python_path root_build_dir
+syn keyword     gnPredefVar root_gen_dir root_out_dir target_gen_dir
+syn keyword     gnPredefVar target_out_dir
+syn keyword     gnPredefVar true false
+hi def link     gnPredefVar         Constant
+
+" Target declarations
+syn keyword     gnTarget action action_foreach copy executable group
+syn keyword     gnTarget shared_library source_set static_library
+hi def link     gnTarget            Type
+
+" Buildfile functions
+syn keyword     gnFunctions assert config declare_args defined exec_script
+syn keyword     gnFunctions foreach get_label_info get_path_info
+syn keyword     gnFunctions get_target_outputs getenv import print
+syn keyword     gnFunctions process_file_template read_file rebase_path
+syn keyword     gnFunctions set_default_toolchain set_defaults
+syn keyword     gnFunctions set_sources_assignment_filter template tool
+syn keyword     gnFunctions toolchain toolchain_args write_file
+hi def link     gnFunctions         Macro
+
+" Variables
+syn keyword     gnVariable all_dependent_configs allow_circular_includes_from
+syn keyword     gnVariable args cflags cflags_c cflags_cc cflags_objc
+syn keyword     gnVariable cflags_objcc check_includes complete_static_lib
+syn keyword     gnVariable configs data data_deps defines depfile deps
+syn keyword     gnVariable forward_dependent_configs_from include_dirs inputs
+syn keyword     gnVariable ldflags lib_dirs libs output_extension output_name
+syn keyword     gnVariable outputs public public_configs public_deps script
+syn keyword     gnVariable sources testonly visibility
+hi def link     gnVariable          Keyword
+
+" Strings
+syn region          gnString start=+L\="+ skip=+\\\\\|\\"+ end=+"+ contains=@Spell
+hi def link     gnString            String
+
+" Comments
+syn keyword     gnTodo              contained TODO FIXME XXX BUG NOTE
+syn cluster     gnCommentGroup      contains=gnTodo
+syn region      gnComment           start="#" end="$" contains=@gnCommentGroup,@Spell
+
+hi def link     gnComment           Comment
+hi def link     gnTodo              Todo
+
+" Operators; I think this is a bit too colourful.
+"syn match gnOperator /=/
+"syn match gnOperator /!=/
+"syn match gnOperator />=/
+"syn match gnOperator /<=/
+"syn match gnOperator /==/
+"syn match gnOperator /+=/
+"syn match gnOperator /-=/
+"syn match gnOperator /\s>\s/
+"syn match gnOperator /\s<\s/
+"syn match gnOperator /\s+\s/
+"syn match gnOperator /\s-\s/
+"hi def link     gnOperator          Operator
+
+syn sync minlines=500
+
+let b:current_syntax = "gn"