Refactor HAS_MOUSE flag handling

Now each widget is responsible to enable/disable its own HAS_MOUSE flag
in response to the kMouseEnter/Leave message received. Also there is no
need to iterate over the parents since these messages are propagated
to the parent

src/ui/manager.cpp

@@ -1012,13 +1012,6 @@ void Manager::setMouse(Widget* widget)
     msg->setPropagateToParent(true);
     msg->setCommonAncestor(commonAncestor);
     enqueueMessage(msg);
-
-    // Remove HAS_MOUSE from all the hierarchy
-    auto a = mouse_widget;
-    while (a && a != commonAncestor) {
-      a->disableFlags(HAS_MOUSE);
-      a = a->parent();
-    }
   }
 
   // If the mouse is captured, we can just put the HAS_MOUSE flag in
@@ -1049,13 +1042,6 @@ void Manager::setMouse(Widget* widget)
                              mousePos,
                              kKeyUninitializedModifier,
                              PointerType::Unknown);
-
-    // Add HAS_MOUSE to all the hierarchy
-    auto a = mouse_widget;
-    while (a && a != commonAncestor) {
-      a->enableFlags(HAS_MOUSE);
-      a = a->parent();
-    }
   }
 }
 

src/ui/tooltips.cpp

@@ -85,7 +85,7 @@ bool TooltipManager::onProcessMessage(Message* msg)
           m_timer->start();
         }
       }
-      break;
+      return false;
     }
 
     case kKeyDownMessage:

src/ui/widget.cpp

@@ -1620,6 +1620,14 @@ bool Widget::onProcessMessage(Message* msg)
       else
         break;
 
+    case kMouseEnterMessage:
+      enableFlags(HAS_MOUSE);
+      return true;
+
+    case kMouseLeaveMessage:
+      disableFlags(HAS_MOUSE);
+      return true;
+
     case kSetCursorMessage:
       // Propagate the message to the parent.
       if (parent())