This change avoids breaking after leading floats in the case where
there is a text indentation.

Doing so fixes the following scenario:

<div style="width: 100px; text-indent: 40px;">
  <div style="float: left; width: 60px; height: 10px;"></div>
  <div style="display: inline-block; width: 60px; height: 20px;"></div>
</div>

In the above example, the following steps will happen:

1. The inline div will attempt to fit on the same line as the float.
   It does not, and a new line opportunity will be created on the next
   line.
2. The inline div overflows this new line opportunity due to the indent.
3. HandleOverflow() checks if the previous element (ie. the float)
   can break after. The float can, so it will attempt to rewind.
4. This causes a break in a later DCHECK.

Not allowing breaks after leading floats in the case of an indentation
fixes the above issue, and appears to match the behavior of other
browsers.

Bug: 1014247
Change-Id: Icf551f5908a0fcb8e0b80a8b9329c965435dd805
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1896509
Reviewed-by: Koji Ishii <kojii@chromium.org>
Commit-Queue: Alison Maher <almaher@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#741487}