Fix AIDL syntax

Since syntax/java.vim was removed, we base the syntax highlighting on
the Vim's builtin syntax/java.vim.

README.md

@@ -2,7 +2,7 @@ This is my top-starred repository on Github, so I've decided to put this ad here
 
 If you work for big corp and seek consulting, please visit following repository: https://github.com/sheerun/consultation
 
-![vim-polyglot](https://i.imgur.com/9RxQK6k.png
+![vim-polyglot](https://i.imgur.com/9RxQK6k.png)
 
 A collection of language packs for Vim.
 

syntax/aidl.vim

@@ -13,15 +13,14 @@ if exists("b:current_syntax")
   finish
 endif
 
-source <sfile>:p:h/java.vim
+if filereadable($VIMRUNTIME . "/syntax/java.vim")
+  source $VIMRUNTIME/syntax/java.vim
+endif
 
-syn keyword aidlParamDir in out inout
-syn keyword aidlKeyword const oneway parcelable
+syn keyword aidlStorageClass in out inout const oneway
+syn keyword aidlInterfaceDecl parcelable union
 
-" Needed for the 'in', 'out', 'inout' keywords to be highlighted.
-syn cluster javaTop add=aidlParamDir
-
-hi def link aidlParamDir StorageClass
-hi def link aidlKeyword Keyword
+hi def link aidlStorageClass javaStorageClass
+hi def link aidlInterfaceDecl javaClassDecl
 
 let b:current_syntax = "aidl"