Revert cursor changes to RenderWidgetHostViewAura.

This is a selective revert of one file from
https://codereview.chromium.org/1945423002, which was breaking cursor
changes on zoom in/zoom out on the Linux version of chrome.

BUG=602727,614654

Review-Url: https://codereview.chromium.org/2027693003
Cr-Commit-Position: refs/heads/master@{#396977}
1 file changed