Revert "Remove mousewheel event name workaround"

This reverts commit 20ce6640688ade1398f15f1ebca299859d497c8b.

Reverted upstream: https://github.com/google/closure-library/commit/4ee0daca0ec1bea486ab670310a6e9bdbaaad720
Merge pull request #2956 from fredj/mousewheel-event-name

Revert "Remove mousewheel event name workaround"
Use the layergroup's extent if no extent provided
Merge pull request #2960 from bartvde/layergroup-extent

LayerGroup extent should be used if extent not set on child layer
Fix pan with select interaction in mousemove mode.
Merge pull request #2965 from tonio/pan_selectinteraction

Fix pan with select interaction in mousemove mode.