Eliminate main window logic from MagicHelper.

The only remaining logic in MagicHelper was calling kernel upon update.
Moved the call to main window using new special signal 'readyForUpdate'
Upon receival of this signal main window will query the kernel and call
MagicHelper.populate_magic_helper()

IPython/qt/console/magic_helper.py

@@ -25,6 +25,7 b' class MagicHelper(QtGui.QDockWidget):'
 
     pasteRequested = QtCore.pyqtSignal(str, name = 'pasteRequested')
     runRequested = QtCore.pyqtSignal(str, name = 'runRequested')
+    readyForUpdate = QtCore.pyqtSignal(name = 'readyForUpdate')
 
     #---------------------------------------------------------------------------
     # 'object' interface
@@ -34,11 +35,6 b' class MagicHelper(QtGui.QDockWidget):'
 
         super(MagicHelper, self).__init__(name, parent)
 
-        # this is a hack. The main_window reference will be used for 
-        # explicit interface to kernel that must be hidden by signal/slot 
-        # mechanism in the future
-        self.main_window = parent
-
         self.data = None
 
         class MinListWidget(QtGui.QListWidget):
@@ -94,21 +90,9 b' class MagicHelper(QtGui.QDockWidget):'
         self.data = {}
         self.search_class.clear()
         self.search_class.addItem("Populating...")
-        self.main_window.active_frontend._silent_exec_callback(
-            'get_ipython().magic("lsmagic")',
-            self.populate_magic_helper
-        )
+        self.readyForUpdate.emit()
 
     def populate_magic_helper(self, data):
-        if not data:
-            return
-
-        if data['status'] != 'ok':
-            self.main_window.log.warn(
-                "%%lsmagic user-expression failed: {}".format(data)
-            )
-            return
-
         self.search_class.clear()
         self.search_list.clear()
                 

IPython/qt/console/mainwindow.py

@@ -713,6 +713,9 b' class MainWindow(QtGui.QMainWindow):'
         self.magic_helper.runRequested[str].connect(
             self.magic_helper_run_requested
         )
+        self.magic_helper.readyForUpdate.connect(
+            self.magic_helper_update_requested
+        )
 
         self.addDockWidget(QtCore.Qt.RightDockWidgetArea, self.magic_helper)
 
@@ -732,8 +735,23 b' class MainWindow(QtGui.QMainWindow):'
             self.active_frontend.execute(text)  
             self._set_active_frontend_focus()
 
+    def magic_helper_update_requested(self):
+        def _handle_data(data):
+            if not data:
+                return
+
+            if data['status'] != 'ok':
+                self.log.warn( 
+                    "%%lsmagic user-expression failed: {}".format(data)
+                )
+                return
+            self.magic_helper.populate_magic_helper(data)
+
+        self.active_frontend._silent_exec_callback(
+            'get_ipython().magic("lsmagic")',
+            _handle_data
+        )
 
-        
     # minimize/maximize/fullscreen actions:
 
     def toggle_menu_bar(self):