FrameLoader: remove FrameLoadRequest::TriggeringEvent

The event is only used by default click handlers and form submission.
This patch replaces event with NavigationPolicy calculated
on the call sites and (unfortunately) WebEventTriggeringInfo.

Replaced one unit test with layout test which exercises real
click instead of simulating it.

Next patch will encapsulate all navigation policy logic in and fix a bug with form submissions ignoring
event modifiers (see issue).

Bug: 849055
Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_slimming_paint_v2;master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Change-Id: Ic64b0eec02d69e58d0dbe283abd7ee157f46f747
Commit-Queue: Dmitry Gozman <>
Reviewed-by: Daniel Cheng <>
Cr-Commit-Position: refs/heads/master@{#566969}
33 files changed