linux_aura: Keep GTK state from leaking between profiles.

The views::LinuxUI* object is global across profiles. However, it stored
profile specific state in the form of a |use_gtk_| variable. This fixes
Gtk2Borders so that they ask their owning view for a ThemeProvider and
expands the ui::ThemeProvider interface so that it exposes the
UsingNativeTheme() call from the ThemeService layer, instead of asking
the views::LinuxUI provider directly, which will likely return stale state.

BUG=340805, 340799

Review URL: https://codereview.chromium.org/171413002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252085 0039d316-1c4b-4281-b951-d872f2087c98
Fix webpagereplay.py so that dns_port can be None.

BUG=339878
NOTRY=True
R=frankf@chromium.org

Review URL: https://codereview.chromium.org/170263006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252086 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 252086