Move showLineTreeAndMark() to LayoutBlockFlow.

third_party/WebKit/Source/core/layout/LayoutObject.cpp

Index: third_party/WebKit/Source/core/layout/LayoutObject.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutObject.cpp b/third_party/WebKit/Source/core/layout/LayoutObject.cpp
index 85469ef8baeb70befcdbb797f57ebe3e3d300a91..97ca75f7f2f80afcfaba3faa426c4eaadf54569a 100644
--- a/third_party/WebKit/Source/core/layout/LayoutObject.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutObject.cpp
@@ -1659,8 +1659,10 @@ void LayoutObject::showLayoutTreeForThis() const
 
 void LayoutObject::showLineTreeForThis() const
 {
-    if (containingBlock())
-        containingBlock()->showLineTreeAndMark(0, 0, 0, 0, this);
+    if (LayoutBlock* cb = containingBlock()) {
+        if (cb->isLayoutBlockFlow())

[wkorman, 2016/05/04 20:30:41]

Does this change behavior of what we output at all? If so consider updating CL
description.

[mstensho (USE GERRIT), 2016/05/04 20:54:25]

In theory, yes. If someone wants to display the line tree they're in when
they're not in a block container (LayoutBlockFlow) (and therefore doesn't
participate in an inline formatting context), we'll now do nothing, rather than
calling showLayoutObject(), which would be the previous behavior. I see no value
in someone doing something as stupid as that, though. :)

This is debug code, FWIW.

+            toLayoutBlockFlow(cb)->showLineTreeAndMark(0, 0, 0, 0, this);

[wkorman, 2016/05/04 20:30:41]

Use nullptr rather than 0. Is it untoward re: consistency of showXxx() methods
to alter param order so we can just pass this and rely on defaults for the
others?

[mstensho (USE GERRIT), 2016/05/04 20:54:25]

Done.
Deserves a separate CL, if anything. There are multiple callers of
showLineTreeAndMark(), and all I want in this CL is to get rid of line layout
code from LayoutBlock.

+    }
 }
 
 void LayoutObject::showLayoutObject() const