Removed top-level 'filetypes' request param

This is now a computed property as well.

examples/example_client.py

@@ -272,7 +272,6 @@ def BuildRequestData( test_filename = None,
   contents = open( test_path ).read()
 
   return {
-    'filetypes': [ filetype ],
     'line_num': line_num,
     'column_num': column_num,
     'filepath': test_path,

ycmd/request_wrap.py

@@ -26,6 +26,7 @@ def __init__( self, request ):
       'line_value': self._CurrentLine,
       'start_column': self._CompletionStartColumn,
       'query': self._Query,
+      'filetypes': self._Filetypes,
     }
 
     self._query = None
@@ -80,6 +81,11 @@ def _Query( self ):
     return self._query
 
 
+  def _Filetypes( self ):
+    path = self[ 'filepath' ]
+    return self[ 'file_data' ][ path ][ 'filetypes' ]
+
+
 def CompletionStartColumn( line_value, column_num ):
   """Returns the 1-based index where the completion query should start. So if
   the user enters:

ycmd/tests/misc_handlers_test.py

@@ -32,7 +32,12 @@
 def SemanticCompletionAvailable_Works_test():
   app = TestApp( handlers.app )
   request_data = {
-    'filetypes': ['python']
+    'filepath': '/foo',
+    'file_data': {
+      '/foo': {
+        'filetypes': ['python'],
+      }
+    }
   }
 
   ok_( app.post_json( '/semantic_completion_available',

ycmd/tests/test_utils.py

@@ -30,7 +30,6 @@ def BuildRequest( **kwargs ):
   request = {
     'line_num': 1,
     'column_num': 1,
-    'filetypes': [ filetype ],
     'filepath': filepath,
     'file_data': {
       filepath: {