Closing a guest session clears all browsing history.

Note: This CL will be merged back to M41. Further work is underway
to completely delete the Guest Profile when all browser windows are
closed, but that will be too large to merge.

BUG=445036
TBR=mlerman@chromium.org
TEST=Open a Guest profile from the User Manager. Perform some browsing, set some cookies, etc. (e.g. sign in to your email). Close all guest browsers (via Exit Guest, closing all the browsers, however you like). Navigate to the same page, and your cookies are disappeared!

Review URL: https://codereview.chromium.org/888843005

Cr-Commit-Position: refs/heads/master@{#316300}
(cherry picked from commit 67fa17a0ca78f16c8a28421d31093b26505f65c3)

Review URL: https://codereview.chromium.org/928423002

Cr-Commit-Position: refs/branch-heads/2272@{#305}
Cr-Branched-From: 827a380cfdb31aa54c8d56e63ce2c3fd8c3ba4d4-refs/heads/master@{#310958}

• chrome/browser/browsing_data/browsing_data_remover.cc[diff]
• chrome/browser/ui/browser.cc[diff]
• chrome/browser/ui/browser_command_controller_browsertest.cc[diff]
• chrome/browser/ui/browser_command_controller_unittest.cc[diff]
• chrome/browser/ui/browser_list.cc[diff]