only set frame title when navigation is not renderer initiated

[diracdeltas]

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Ran git rebase -i to squash commits (if needed).

Test Plan:

1. go to http://web.mit.edu/zyan/Public/googlespoof.html
2. click on the link
3. when the new window stops loading, the tab title should be the tab URL instead of 'fake'

partial fix for #4973. this prevents the page-that-is-being-spoofed from displaying the title from the spoofing page.

requires brave/muon#83

auditors: @bbondy

[bbondy]

looks great but waiting for electron 1.4.21 to merge this.

[diracdeltas]

merging now that electron has been updated on master