Protect against View#showContextMenu NPE

View#showContextMenu fails if View#getParent is null.  Do a null check before
showing the context menu.

BUG=327082
NOTRY=true

Review URL: https://codereview.chromium.org/114043003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@242853 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 242853
Include label min widths in the infobar "content minimum width" so that infobars
are only shrinkable to the point of having ellipses for all labels.

For extension infobars, this does something similar but with the extension view
min width.  (I'm not sure whether that's actually set correctly, but this is at
least more theoretically correct regardless.)

BUG=none
TEST=Trigger a translate infobar, shrink the window width, the infobar should not shrink beyond having an ellipsis in each label's location
R=msw@chromium.org

Review URL: https://codereview.chromium.org/120773006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@242854 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 242854