Fixes tab dragging out of a window with maximzied bounds

The breaking change was a fix for http://crbug.com/392599 (https://codereview.chromium.org/424463002/) that causes a browser window to be maximized at creation time if its size is as big as a work area. When a tab is dragged into a new browser window this new window may be maximized and so not draggable.

BUG=491502
TEST=DetachToBrowserTabDragControllerTest.DetachFromFullsizeWindow

Review URL: https://codereview.chromium.org/1156893008

Cr-Commit-Position: refs/heads/master@{#333220}
3 files changed