Not all inline break tokens have ComputedStyle.

This has been the case ever since the ComputedStyle field was added:
https://chromium-review.googlesource.com/846585

AddBreakBeforeChild() in NGFragmentBuilder (since moved to
NGBoxFragmentBuilder) passes nullptr for ComputedStyle.

So just add a nullptr check.

Bug: 1175666
Change-Id: Ie0d46c93a64f25de09f3193c5cb329e9ac37b88b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2683984
Reviewed-by: Koji Ishii <kojii@chromium.org>
Commit-Queue: Morten Stenshorne <mstensho@chromium.org>
Cr-Commit-Position: refs/heads/master@{#852354}
diff --git a/css/css-break/no-room-for-line-in-first-fragmentainer-crash.html b/css/css-break/no-room-for-line-in-first-fragmentainer-crash.html
new file mode 100644
index 0000000..bc7b9aa
--- /dev/null
+++ b/css/css-break/no-room-for-line-in-first-fragmentainer-crash.html
@@ -0,0 +1,9 @@
+<!DOCTYPE html>
+<link rel="author" title="Morten Stenshorne" href="mailto:mstensho@chromium.org">
+<link rel="help" href="https://bugs.chromium.org/p/chromium/issues/detail?id=1175666">
+<div style="width:500px; columns:3; column-fill:auto; height:100px; line-height:100px;">
+  <div style="padding-top:50px;">
+    <canvas style="float:left; width:200px; height:100px;"></canvas>
+    <span style="display:inline-block; width:100px; height:10px;"></span>
+  </div>
+</div>