Fix for moving to previous url from PDF page in OOP case.

alt,shift,ctrl are not considered while handling left or right arrow
key in OOP case in PDF.
Check added so that when left/right arrow key is selected then navigation
with in the page will happen when alt,ctrl,shift are not selected.
else default handling happen.

BUG=446162

Review URL: https://codereview.chromium.org/830853003

Cr-Commit-Position: refs/heads/master@{#310045}
1 file changed