Update status class when window gains focus

This will keep the tree view in sync when Git operations are
performed outside of the editor.

src/packages/tree-view/spec/tree-view-spec.coffee

@@ -887,6 +887,13 @@ describe "TreeView", ->
       it "adds a custom style", ->
         expect(treeView.find('.file:contains(tree-view.txt)')).toHaveClass 'modified'
 
+      describe "when the window gains focus after the contents are restored to a clean state", ->
+        it "removes the custom style", ->
+          expect(treeView.find('.file:contains(tree-view.txt)')).toHaveClass 'modified'
+          fs.write modifiedFile, originalFileContent
+          $(window).trigger 'focus'
+          expect(treeView.find('.file:contains(tree-view.txt)')).not.toHaveClass 'modified'
+
     describe "when a file is new", ->
       it "adds a custom style", ->
         expect(treeView.find('.file:contains(.gitignore)')).toHaveClass 'new'

src/packages/tree-view/src/file-view.coffee

@@ -9,13 +9,14 @@ class FileView extends View
   @content: ({file} = {}) ->
     @li class: 'file entry', =>
       @span file.getBaseName(), class: 'name', outlet: 'fileName'
-      @span "", class: 'highlight'
+      @span '', class: 'highlight'
 
   file: null
 
-  initialize: ({@file, project} = {}) ->
-    path = @getPath()
-    extension = fs.extension(path)
+  initialize: ({@file, @project} = {}) ->
+    @subscribe $(window), 'focus', => @updateStatus()
+
+    extension = fs.extension(@getPath())
     if fs.isCompressedExtension(extension)
       @fileName.addClass('compressed-name')
     else if fs.isImageExtension(extension)
@@ -25,11 +26,16 @@ class FileView extends View
     else
       @fileName.addClass('text-name')
 
-    if project.repo.isPathIgnored(path)
+    @updateStatus()
+
+  updateStatus: ->
+    path = @getPath()
+    @removeClass('ignored modified new')
+    if @project.repo.isPathIgnored(path)
       @addClass('ignored')
-    else if project.repo.isPathModified(path)
+    else if @project.repo.isPathModified(path)
       @addClass('modified')
-    else if project.repo.isPathNew(path)
+    else if @project.repo.isPathNew(path)
       @addClass('new')
 
   getPath: ->