Attempting to reland the Overview Button Change.

The inital change was landed as 256420.
The change was reverted by 256535, as a Win 7 release test failed on the build server. Another change in ash was also reverted.
I was unable to reproduce the test failure on a local Win 7 machine.

"Revert of Add a new status area control for Overview Mode. This control is only available (https://codereview.chromium.org/180743016/)"

This reverts commit 65e11004319c51eb14787d51102a3db9100da480.

BUG=337590
TBR=oshima
R=flackr

Review URL: https://codereview.chromium.org/196473011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@257012 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 257012
Remove GetContentSettingsStore() From ExtensionService

BUG=351891
TBR=jochen@chromium.org (mechanical change to host_content_settings_map.cc)

Review URL: https://codereview.chromium.org/196653007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@257013 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 257013