Fix sticky keys crash when handling synthetic events without a native event.

ash/sticky_keys/sticky_keys_controller.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/sticky_keys/sticky_keys_controller.h"
 
 #if defined(USE_X11)
 #include <X11/extensions/XInput2.h>
 #include <X11/Xlib.h>
 #undef RootWindow
@@ skipping 51 matching lines @@
 void StickyKeysHandlerDelegateImpl::DispatchKeyEvent(ui::KeyEvent* event,
                                                      aura::Window* target) {
   DispatchEvent(event, target);
 }
 
 void StickyKeysHandlerDelegateImpl::DispatchMouseEvent(ui::MouseEvent* event,
                                                        aura::Window* target) {
   DCHECK(target);
   // We need to send a new, untransformed mouse event to the host.
   if (event->IsMouseWheelEvent()) {
-    ui::MouseWheelEvent new_event(event->native_event());
-    DispatchEvent(&new_event, target);
+    if (event->HasNativeEvent()) {
+      ui::MouseWheelEvent new_event(event->native_event());
+      DispatchEvent(&new_event, target);
+    } else {
+      aura::Window* source = static_cast<aura::Window*>(event->target());
+      ui::MouseWheelEvent new_event(*static_cast<ui::MouseWheelEvent*>(event),
+                                    source,
+                                    source->GetRootWindow(),
+                                    event->type(),
+                                    event->flags());

[sadrul, 2014/04/07 21:57:33]

It looks like this ctor for MouseWheelEvent is not used anywhere. Mind changing
the ctor so it doesn't take the EventType or the flags as parameters?

[Tim Song, 2014/04/07 22:23:27]

Done.

+      // Transform the location back to host coordinates before dispatching.
+      new_event.UpdateForRootTransform(source->GetHost()->GetRootTransform());
+      DispatchEvent(&new_event, target);
+    }
   } else {
-    ui::MouseEvent new_event(event->native_event());
-    DispatchEvent(&new_event, target);
+    if (event->HasNativeEvent()) {
+      ui::MouseEvent new_event(event->native_event());
+      DispatchEvent(&new_event, target);
+    } else {
+      aura::Window* source = static_cast<aura::Window*>(event->target());
+      ui::MouseEvent new_event(*event, source, source->GetRootWindow());
+      // Transform the location back to host coordinates before dispatching.
+      new_event.UpdateForRootTransform(source->GetHost()->GetRootTransform());
+      DispatchEvent(&new_event, target);
+    }

[sadrul, 2014/04/07 21:57:33]

You can always just create the new event out of the modified event and dispatch
that, right? Does creating the event from the X event give you any benefit?

[Tim Song, 2014/04/07 22:23:27]

Done. You're right, it should be equivalent in this case.

   }
 }
 
 void StickyKeysHandlerDelegateImpl::DispatchScrollEvent(
     ui::ScrollEvent* event,
     aura::Window* target)  {
   DispatchEvent(event, target);
 }
 
 void StickyKeysHandlerDelegateImpl::DispatchEvent(ui::Event* event,
@@ skipping 432 matching lines @@
           &xievent->mods.effective));
     }
   }
 #elif defined(USE_OZONE)
   NOTIMPLEMENTED() << "Modifier key is not handled";
 #endif
   event->set_flags(event->flags() | modifier_flag_);
 }
 
 }  // namespace ash