Add mojom syntax highlighting for VIM

+ Bring over original syntax highlighting for .mojom files from
  https://chromium.googlesource.com
+ Add definitions for a few data types and literals

BUG=
R=cpu@chromium.org

Review URL: https://codereview.chromium.org/1313743004 .

tools/vim/mojom/ftdetect/mojomfiletype.vim

diff --git a/tools/vim/mojom/ftdetect/mojomfiletype.vim b/tools/vim/mojom/ftdetect/mojomfiletype.vim
new file mode 100644
index 0000000..3fda0b4
--- /dev/null
+++ b/tools/vim/mojom/ftdetect/mojomfiletype.vim
@@ -0,0 +1,27 @@
+" Copyright 2015 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.
+" We take care to preserve the user's fileencodings and fileformats,
+" because those settings are global (not buffer local), yet we want
+" to override them for loading mojom files, which should be UTF-8.
+"
+let s:current_fileformats = ''
+let s:current_fileencodings = ''
+
+" define fileencodings to open as utf-8 encoding even if it's ascii.
+function! s:mojomfiletype_pre()
+  let s:current_fileformats = &g:fileformats
+  let s:current_fileencodings = &g:fileencodings
+  set fileencodings=utf-8 fileformats=unix
+  setlocal filetype=mojom
+endfunction
+
+" restore fileencodings as others
+function! s:mojomfiletype_post()
+  let &g:fileformats = s:current_fileformats
+  let &g:fileencodings = s:current_fileencodings
+endfunction
+
+au BufNewFile *.mojom setlocal filetype=mojom fileencoding=utf-8 fileformat=unix
+au BufRead *.mojom call s:mojomfiletype_pre()
+au BufReadPost *.mojom call s:mojomfiletype_post()

tools/vim/mojom/syntax/mojom.vim

diff --git a/tools/vim/mojom/syntax/mojom.vim b/tools/vim/mojom/syntax/mojom.vim
new file mode 100644
index 0000000..f8b5a67
--- /dev/null
+++ b/tools/vim/mojom/syntax/mojom.vim
@@ -0,0 +1,64 @@
+" Copyright 2015 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.
+" Vim syntax file " Language: Mojom
+" To get syntax highlighting for .mojom files, add the following to your .vimrc
+" file:
+"     set runtimepath^=/path/to/src/tools/vim/mojom
+syn case match
+
+syntax region mojomFold start="{" end="}" transparent fold
+
+" keyword definitions
+syntax keyword mojomType        bool int8 int16 int32 int64 uint8 uint16 uint32 uint64 float double array
+syntax keyword mojomType        handle map string
+syntax match mojomImport        "^\(import\)\s"
+syntax keyword mojomKeyword     const module interface enum struct union
+syntax match mojomOperator      /=>/
+syntax match mojomOperator      /?/
+
+" Comments
+syntax keyword mojomTodo           contained TODO FIXME XXX
+syntax region  mojomComment        start="/\*"  end="\*/" contains=mojomTodo,mojomDocLink,@Spell
+syntax match   mojomLineComment    "//.*" contains=mojomTodo,@Spell
+syntax match   mojomLineDocComment "///.*" contains=mojomTodo,mojomDocLink,@Spell
+syntax region  mojomDocLink        contained start=+\[+ end=+\]+
+
+" Strings
+syn region mojomString start=+L\="+ skip=+\\\\\|\\"+ end=+"+ contains=@Spell
+hi def link mojomString            String
+
+" Numbers
+syntax match mojomFloat     '-\?\d*\.\d\+\>'
+syntax match mojomHex       '\<0x[0-9a-fA-F]\+\>'
+syntax match mojomInt       '-\?\<\(0\>\|[1-9]\d*\)'
+
+" syntax match mojomNumber '\<0\>'
+
+" Literals
+syntax keyword mojomLiteral true false
+syntax keyword mojomLiteral float.INFINITY float.NEGATIVE_INFINITY float.NAN
+syntax keyword mojomLiteral double.INFINITY double.NEGATIVE_INFINITY double.NAN
+
+" The default highlighting.
+highlight default link mojomTodo            Todo
+highlight default link mojomComment         Comment
+highlight default link mojomLineComment     Comment
+highlight default link mojomLineDocComment  Comment
+highlight default link mojomDocLink         SpecialComment
+highlight default link mojomType            Type
+highlight default link mojomImport          Include
+highlight default link mojomKeyword         Keyword
+highlight default link mojomOperator        Operator
+highlight default link mojomLiteral         Constant
+highlight default link mojomFloat           Float
+highlight default link mojomHex             Number
+highlight default link mojomInt             Number
+
+
+let b:current_syntax = "mojom"
+let b:spell_options = "contained"
+
+syn sync minlines=500
+
+let b:current_syntax = "mojom"