Prevent Android tests from being broken by data URL deprecation

These tests will be broken when content initiated navigations to data URLs
are blocked. This CL navigates the tests to an existing file instead of
data URLs. It also removes some unused variables.

BUG=594215

Review-Url: https://codereview.chromium.org/2827393003
Cr-Commit-Position: refs/heads/master@{#466200}
3 files changed