IndexedDBBrowserTest.Bug84933Test is flaky

BUG=310381
TBR=pfeldman@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/34783005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@230289 0039d316-1c4b-4281-b951-d872f2087c98
Check for portal detector instance not being NULL as it may be disabled from flags.

BUG=310169

Review URL: https://codereview.chromium.org/35383002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@230290 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 230290