Add check for file:-navigations from PDFs

BUG=654279
TEST=./browser_tests --gtest_filter=PDFExtensionTest.Navigator
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2402873002
Cr-Commit-Position: refs/heads/master@{#425287}
3 files changed