Aura: don't synthesize mouse moves while holding pointer.

ui/aura/root_window_unittest.cc

Index: ui/aura/root_window_unittest.cc
diff --git a/ui/aura/root_window_unittest.cc b/ui/aura/root_window_unittest.cc
index a5a6283269af1f664d163dd7bf39e56deb298296..7d6cbd104907e0c73c598055e6816825139b5347 100644
--- a/ui/aura/root_window_unittest.cc
+++ b/ui/aura/root_window_unittest.cc
@@ -672,6 +672,18 @@ TEST_F(RootWindowTest, MouseMovesHeld) {
   filter->Reset();
   RunAllPendingInMessageLoop();
   EXPECT_TRUE(filter->events().empty());
+
+  // Check that no events are synthesized while holding, and all held move
+  // events are dropped on window changes.
+  dispatcher()->HoldPointerMoves();
+  DispatchEventUsingWindowDispatcher(&mouse_dragged_event);
+  DispatchEventUsingWindowDispatcher(&mouse_dragged_event2);
+  dispatcher()->OnWindowBoundsChanged(window.get(), true);
+  RunAllPendingInMessageLoop();
+  EXPECT_TRUE(filter->events().empty());
+  dispatcher()->ReleasePointerMoves();
+  RunAllPendingInMessageLoop();
+  EXPECT_TRUE(filter->events().empty());
 }
 
 TEST_F(RootWindowTest, TouchMovesHeld) {