Refactor to remove RenderWidget::PageScaleFactorChanged().

This refactor moves the logic in RenderWidget::PageScaleFactorChanged()
to RenderWidget::SetPageScaleStateAndLimits(). This removes the need for
RenderViewImpl::PageScaleFactorChanged() to call GetWidget().

This is a re-land of
https://chromium-review.googlesource.com/c/chromium/src/+/1614080.

TBR=dcheng@chromium.org
TBR=collinbaker@chromium.org

Bug: 924336
Change-Id: Id076ddc805c62069984181914f3722d4d081a3b3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1617064
Reviewed-by: James MacLean <wjmaclean@chromium.org>
Commit-Queue: James MacLean <wjmaclean@chromium.org>
Cr-Commit-Position: refs/heads/master@{#660834}
11 files changed