ColorChooserWin::End should act like the dialog has closed

This is only a problem on Windows.

When the page closes itself while the color chooser dialog is open,
ColorChooserDialog::DidCloseDialog was called after the listener has been destroyed.

ColorChooserWin::End() will not actually close the color chooser dialog (because we can't) but act like it did so we can do the necessary cleanup.

BUG=279263
R=jschuh@chromium.org, pkasting@chromium.org

Review URL: https://codereview.chromium.org/23785003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@220639 0039d316-1c4b-4281-b951-d872f2087c98
 void ColorChooserWin::OnColorChosen(SkColor color) {
   if (web_contents_)
     web_contents_->DidChooseColorInColorChooser(color);
}

 void ColorChooserWin::OnColorChosen(SkColor color) {
   if (web_contents_)
     web_contents_->DidChooseColorInColorChooser(color);
}
