Have remove_and_cancel_tooltip() return a boolean

IPython/html/static/notebook/js/codecell.js

@@ -179,12 +179,7 var IPython = (function (IPython) {
                 return true;
             };
         } else if (event.which === key.ESC) {
-            if (!IPython.tooltip._hidden) {
-              IPython.tooltip.remove_and_cancel_tooltip(true);
-              return true;
-            } else {
-              return false;
-            }
+            return IPython.tooltip.remove_and_cancel_tooltip(true);
         } else if (event.which === key.DOWNARROW && event.type === 'keydown') {
             // If we are not at the bottom, let CM handle the down arrow and
             // prevent the global keydown handler from handling it.

IPython/html/static/notebook/js/tooltip.js

@@ -161,16 +161,23 var IPython = (function (IPython) {
         this.code_mirror = null;
     }
 
+    // return true on successfully removing a visible tooltip; otherwise return
+    // false.
     Tooltip.prototype.remove_and_cancel_tooltip = function (force) {
         // note that we don't handle closing directly inside the calltip
         // as in the completer, because it is not focusable, so won't
         // get the event.
+        if (this._hidden === false) {
         if (this._sticky == false || force == true) {
             this.cancel_stick();
             this._hide();
         }
         this.cancel_pending();
         this.reset_tabs_function();
+          return true;
+        } else {
+          return false;
+        }
     }
 
     // cancel autocall done after '(' for example.