Remove unneeded include

There should be no behavior change from this CL.

Change-Id: I009e877e711ef85deb4a2391412a598757d20999
Cq-Do-Not-Cancel-Tryjobs: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2601717
Commit-Queue: Ian Kilpatrick <ikilpatrick@chromium.org>
Auto-Submit: Mason Freed <masonfreed@chromium.org>
Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#839161}

third_party/blink/renderer/core/layout/layout_block_flow.cc

@@ -38,7 +38,6 @@
 #include "third_party/blink/renderer/core/editing/editor.h"
 #include "third_party/blink/renderer/core/frame/local_frame.h"
 #include "third_party/blink/renderer/core/frame/local_frame_view.h"
-#include "third_party/blink/renderer/core/html/html_dialog_element.h"
 #include "third_party/blink/renderer/core/html/shadow/shadow_element_names.h"
 #include "third_party/blink/renderer/core/layout/hit_test_location.h"
 #include "third_party/blink/renderer/core/layout/layout_analyzer.h"