Cleanup: Remove an inaccurate DCHECK and rename a method.
The DCHECK was triggered by https://code.google.com/p/chromium/codesearch#chromium/src/chrome/browser/ui/cocoa/profiles/avatar_icon_controller.mm&l=123
This CL also renames AvatarBaseController::showAvatarBubble to showAvatarBubbleAnchoredAt to make clear what the purpose of the first parameter is.
BUG=393411
Review URL: https://codereview.chromium.org/
486683002
Cr-Commit-Position: refs/heads/master@{#290821}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@290821 0039d316-1c4b-4281-b951-d872f2087c98