[LayoutNG] Make NonInlineBlockFlow() in ax_node_object.cc to use IsAtomicInlineLevel()

This patch makes file local funciton |NonInlineBlockFlow()| in
"ax_node_object.cc" to use |IsAtomicInlineLevel()| to make this funciton to
work both legacy layout and LayoutNG.

Note: |IsAtomicInlineLevel()| is a bitfiled in |LayoutObject|. It is set by
|LayoutBlock::StyleWillChange()| when compute style has "display:inline-block".

Therefore, in legacy layout, when |IsAtomicInlineLevel()| is true for
|LayoutBlockFlow|, |!InlineBoxWrapper() == !IsAtomicInlineLevel()|.


In LayoutNG, |IsAtomicInlineLevel()| is used for computing physical fragment
box type in |BoxTypeFromLayoutObject()|. |BoxTypeFromLayoutObject()| returns
|NGBoxyType::kAtomicInline| for |IsAtomicInlineLevel()|.

Bug: 591099
Change-Id: Ieafd8a414662df7e0d4f48f1b15657a602265559
Reviewed-on: https://chromium-review.googlesource.com/1092224Reviewed-by: Koji Ishii <kojii@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: Yoshifumi Inoue <yosin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#566770}

third_party/blink/renderer/modules/accessibility/ax_node_object.cc

@@ -1690,14 +1690,13 @@ AccessibilityRole AXNodeObject::AriaRoleAttribute() const {
   return aria_role_;
 }
 
-// Returns the nearest LayoutBlockFlow ancestor which does not have an
-// inlineBoxWrapper - i.e. is not itself an inline object.
+// Returns the nearest block-level LayoutBlockFlow ancestor
 static LayoutBlockFlow* NonInlineBlockFlow(LayoutObject* object) {
   LayoutObject* current = object;
   while (current) {
     if (current->IsLayoutBlockFlow()) {
       LayoutBlockFlow* block_flow = ToLayoutBlockFlow(current);
-      if (!block_flow->InlineBoxWrapper())
+      if (!block_flow->IsAtomicInlineLevel())
         return block_flow;
     }
     current = current->Parent();