Bug 1082510 - When we detect a chrome popup at the current event coordinates and remote content has the mouse captured, release capture. r=Enn

layout/base/nsPresShell.cpp

@@ -7368,6 +7368,12 @@ PresShell::HandleEvent(nsIFrame* aFrame,
         frame == mFrameConstructor->GetRootFrame()) {
       nsIFrame* popupFrame =
         nsLayoutUtils::GetPopupFrameForEventCoordinates(rootPresContext, aEvent);
+      // If a remote browser is currently capturing input break out if we
+      // detect a chrome generated popup.
+      if (popupFrame && capturingContent &&
+          EventStateManager::IsRemoteTarget(capturingContent)) {
+        capturingContent = nullptr;
+      }
       // If the popupFrame is an ancestor of the 'frame', the frame should
       // handle the event, otherwise, the popup should handle it.
       if (popupFrame &&