Chrome Version: 60.0.3101.0
OS: ChromiumOS

What steps will reproduce the problem?
(1) Launch an Android application that uses SYSTEM_ALERT type window, like Messenger in Chat Head mode
(2) Once in Chat Head mode try to click the Edit Box
(3) Focus won't appear.

What is the expected result?
Focus should appear.

What happens instead?
Focus doesn't appear.

Please use labels and text to provide additional information.

The easiest way to reproduce it, is with an Android application, but it is not related to Android.

But happens because MOUSE_PRESSED location_f() is different than MOUSE_RELEASED location_f(). And when they are not exactly the same, a MOUSE_MOVE event is generated.
And this MOUSE_MOVE event triggers a bug in Android, but could trigger similar bugs on other Chrome windows, specially if using a big screen.



Trace that shows the bug:


window_event_dispatcher.cc(466)] WindowEventDispatcher::GetRootForEvent()172.407196,591.895264    <--- Where the PRESS-Event was generated
window.cc(1096)] Window::ConvertEventToTarget()RootWindow-0 (0x21001f324b00) layer bounds(0, 0, 1366, 768) (172.407196,591.895264) --> ScreenRotationContainer (0x21001f324448) layer bounds(0, 0, 1366, 768) (172.407196,591.895264)
window.cc(1096)] Window::ConvertEventToTarget()ScreenRotationContainer (0x21001f324420) layer bounds(0, 0, 1366, 768) (172.407196,591.895264) --> PowerButtonAnimationContainer (0x21001f402868) layer bounds(0, 0, 1366, 768) (172.407196,591.895264)
...
window.cc(1096)] Window::ConvertEventToTarget()SystemModalContainer (0x21001f3bf840) layer bounds(0, 0, 1366, 768) (172.407196,591.895264) --> ExoShellSurface (0x210022bb1708) layer bounds(9937, 117, 63, 651) (-9764.592773,474.895264)
window.cc(1096)] Window::ConvertEventToTarget()ExoShellSurface (0x210022bb16e0) layer bounds(9937, 117, 63, 651) (-9764.592773,474.895264) --> ExoSurface (0x210022cdd708) layer bounds(-9937, -117, 1366, 768) (172.407227,591.895264)
window.cc(1096)] Window::ConvertEventToTarget()ExoSurface (0x210022cdd6e0) layer bounds(-9937, -117, 1366, 768) (172.407227,591.895264) --> ExoSurface (0x210022cdd708) layer bounds(-9937, -117, 1366, 768) (172.407227,591.895264)
window_targeter.cc(40)] WindowTargeter::FindTargetForLocatedEvent() "ExoSurface" = (172.407227,591.895264)

event_dispatcher.cc(50)] EventDispatcherDelegate::DispatchEvent()172.407227,591.895264   <-- DISPATCHES the event to the newly converted coordinate. Notice the rounding error! 172.407196 vs. 172.407227

window_event_dispatcher.cc(943)] WindowEventDispatcher::PreDispatchMouseEvent() ET_MOUSE_PRESSED
pointer.cc(314)] Pointer::GetEffectiveTargetForEvent()
pointer.cc(143)] >>> OnMouseEvent() ev: 172.407227,591.895264 lo_: 172.407227,591.895264
pointer.cc(180)] IsMouseEvent(): ev: 172.407227,591.895264 lo_: 172.407227,591.895264
pointer.cc(196)] PRESSED/RELEASED: ev: 172.407227,591.895264 lo_: 172.407227,591.895264
pointer.cc(324)] Pointer::UpdateCursorScale()
pointer.cc(261)] <<< OnMouseEvent() ev: 172.407227,591.895264 lo_: 172.407227,591.895264

window_event_dispatcher.cc(466)] WindowEventDispatcher::GetRootForEvent()172.407196,591.895264    <-- RELEASE EVENT is generated using the original coordinates (no rounding error)
window.cc(1096)] Window::ConvertEventToTarget()RootWindow-0 (0x21001f324b00) layer bounds(0, 0, 1366, 768) (172.407196,591.895264) --> ExoSurface (0x210022cdd708) layer bounds(-9937, -117, 1366, 768) (172.407196,591.895264)

      ^
      |
It didn't do the whole conversion here... it went directly from "RootWindow-0" to the correct "ExoSurface", so there is no rounding error

window_targeter.cc(29)] WindowTargeter::FindTargetForLocatedEvent() "ExoSurface" = (172.407196,591.895264)
event_dispatcher.cc(50)] EventDispatcherDelegate::DispatchEvent()172.407196,591.895264
window_event_dispatcher.cc(528)] WindowEventDispatcher::PreDispatchEvent()172.407196,591.895264
window_event_dispatcher.cc(858)] WindowEventDispatcher::PreDispatchMouseEvent() 172.407196,591.895264
window_event_dispatcher.cc(952)] WindowEventDispatcher::PreDispatchMouseEvent() ET_MOUSE_RELEASED
pointer.cc(314)] Pointer::GetEffectiveTargetForEvent()
pointer.cc(143)] >>> OnMouseEvent() ev: 172.407196,591.895264 lo_: 172.407227,591.895264
pointer.cc(180)] IsMouseEvent(): ev: 172.407196,591.895264 lo_: 172.407227,591.895264
pointer.cc(186)] MOVE: ev: 172.407196,591.895264 lo_: 172.407227,591.895264                     <-- Compares new event (original) vs. the cached one. They are differnet. Generates MOVE event
pointer.cc(196)] PRESSED/RELEASED: ev: 172.407196,591.895264 lo_: 172.407196,591.895264
pointer.cc(324)] Pointer::UpdateCursorScale()
pointer.cc(261)] <<< OnMouseEvent() ev: 172.407196,591.895264 lo_: 172.407196,591.895264
window_event_dispatcher.cc(569)] WindowEventDispatcher::PostDispatchEvent()172.407196,591.895264
window_event_dispatcher.cc(511)] WindowEventDispatcher::OnEventProcessingFinished()172.407196,591.895264


original value:  x=172.407196, transformed value with rounding error: x=172.407227, and error of ~0.00003... might vary a bit depending where the location is.