Fix brush interaction
Fix brush interaction

Due to an error made in the drag gesture handler refactoring, brushing
did not work correctly and only dragged one of the handles. This CL
fixes this issue and correctly reassigns both handle positions.

Change-Id: I0af16f7385423dc2116a65b754d2d663a5bd1b27
google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto