Put all navigation parameters to WebNavigationParams

- Replaced multiple parameters with a single struct.
- Merged LoadHTMLString, CommitNavigation and CommitDataNavigation
  methods.
- Helper constructor turning WebNavigationInfo to WebNavigationParams.
- Moved srcdoc handling from FrameLoader to DocumentLoader.

Bug: 855189
TBR=tommycli@chromium.org,thestig@chromium.org

Change-Id: If009a2da035b223ce50d60c6eb9bf474fd1539d2
Reviewed-on: https://chromium-review.googlesource.com/c/1274609
Commit-Queue: Dmitry Gozman <dgozman@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Arthur Sonzogni <arthursonzogni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#615764}
32 files changed