hunks: add support for quickfixsigns

Closes: https://github.com/bling/vim-airline/pull/754

README.md

@@ -7,7 +7,12 @@ Lean & mean status/tabline for vim that's light as air.
 # Features
 
 *  Tiny core written with extensibility in mind ([open/closed principle][8]).
-*  Integrates with a variety of plugins, including: [vim-bufferline][6], [fugitive][4], [unite][9], [ctrlp][10], [minibufexpl][15], [gundo][16], [undotree][17], [nerdtree][18], [tagbar][19], [vim-gitgutter][29], [vim-signify][30], [syntastic][5], [eclim][34], [lawrencium][21], [virtualenv][31], [tmuxline][35], [taboo.vim][37], [ctrlspace][38] and more.
+*  Integrates with a variety of plugins, including: [vim-bufferline][6],
+   [fugitive][4], [unite][9], [ctrlp][10], [minibufexpl][15], [gundo][16],
+   [undotree][17], [nerdtree][18], [tagbar][19], [vim-gitgutter][29],
+   [vim-signify][30], [quickfixsigns][39], [syntastic][5], [eclim][34],
+   [lawrencium][21], [virtualenv][31], [tmuxline][35], [taboo.vim][37],
+   [ctrlspace][38] and more.
 *  Looks good with regular fonts and provides configuration points so you can use unicode or powerline symbols.
 *  Optimized for speed; it loads in under a millisecond.
 *  Extensive suite of themes for popular color schemes including [solarized][23] (dark and light), [tomorrow][24] (all variants), [base16][32] (all variants), [molokai][25], [jellybeans][26] and others; have a look at the [screenshots][14] in the wiki.
@@ -223,3 +228,4 @@ MIT License. Copyright (c) 2013-2015 Bailey Ling.
 [36]: https://github.com/edkolev/promptline.vim
 [37]: https://github.com/gcmt/taboo.vim
 [38]: https://github.com/szw/vim-ctrlspace
+[39]: https://github.com/tomtom/quickfixsigns_vim

autoload/airline/extensions.vim

@@ -159,7 +159,7 @@ function! airline#extensions#load()
   endif
 
   if (get(g:, 'airline#extensions#hunks#enabled', 1) && get(g:, 'airline_enable_hunks', 1))
-        \ && (exists('g:loaded_signify') || exists('g:loaded_gitgutter') || exists('g:loaded_changes'))
+        \ && (exists('g:loaded_signify') || exists('g:loaded_gitgutter') || exists('g:loaded_changes') || exists('g:loaded_quickfixsigns'))
     call airline#extensions#hunks#init(s:ext)
   endif
 

autoload/airline/extensions/hunks.vim

@@ -1,7 +1,7 @@
 " MIT License. Copyright (c) 2013-2015 Bailey Ling.
 " vim: et ts=2 sts=2 sw=2
 
-if !get(g:, 'loaded_signify', 0) && !get(g:, 'loaded_gitgutter', 0) && !get(g:, 'loaded_changes', 0)
+if !get(g:, 'loaded_signify', 0) && !get(g:, 'loaded_gitgutter', 0) && !get(g:, 'loaded_changes', 0) && !get(g:, 'loaded_quickfixsigns', 0)
   finish
 endif
 
@@ -53,6 +53,8 @@ function! s:get_hunks()
       let s:source_func = 's:get_hunks_gitgutter'
     elseif exists('*changes#GetStats')
       let s:source_func = 's:get_hunks_changes'
+    elseif exists('*quickfixsigns#vcsdiff#GetHunkSummary')
+      let s:source_func = 'quickfixsigns#vcsdiff#GetHunkSummary'
     else
       let s:source_func = 's:get_hunks_empty'
     endif

doc/airline.txt

@@ -358,6 +358,7 @@ csv.vim <https://github.com/chrisbra/csv.vim>
 vim-gitgutter <https://github.com/airblade/vim-gitgutter>
 vim-signify <https://github.com/mhinz/vim-signify>
 changesPlugin <https://github.com/chrisbra/changesPlugin>
+quickfixsigns <https://github.com/tomtom/quickfixsigns_vim>
 
 * enable/disable showing a summary of changed hunks under source control. >
   let g:airline#extensions#hunks#enabled = 1