Remove WebLocalFrameClient::WillSubmitForm

RenderFrameImpl already knows about form submission during
DecidePolicyForNavigation callback.

Bug: 855189
Change-Id: I2bd71a7deb381a58988a03ea58e58079b2ede031
Reviewed-on: https://chromium-review.googlesource.com/c/1260383
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Commit-Queue: Dmitry Gozman <dgozman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#597094}
9 files changed