Invalidate first line display item clients when first line style changes

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

Index: third_party/WebKit/Source/core/layout/LayoutObject.h
diff --git a/third_party/WebKit/Source/core/layout/LayoutObject.h b/third_party/WebKit/Source/core/layout/LayoutObject.h
index 452d1633e847ccc7eaea35cea054db101f70c4d0..2a922ed1f5e23352908a3fcb2ae1640f493a5d1b 100644
--- a/third_party/WebKit/Source/core/layout/LayoutObject.h
+++ b/third_party/WebKit/Source/core/layout/LayoutObject.h
@@ -341,10 +341,6 @@ public:
         return hasBoxDecorationBackground() || style()->hasVisualOverflowingEffect();
     }
 
-    // Obtains the nearest enclosing block (including this block) that contributes a first-line style to our inline
-    // children.
-    virtual LayoutBlock* firstLineBlock() const;
-
     // LayoutObject tree manipulation
     //////////////////////////////////////////
     virtual bool canHaveChildren() const { return virtualChildren(); }
@@ -750,6 +746,14 @@ public:
     virtual LayoutMultiColumnSpannerPlaceholder* spannerPlaceholder() const { return nullptr; }
     bool isColumnSpanAll() const { return style()->columnSpan() == ColumnSpanAll && spannerPlaceholder(); }
 
+    // We include isLayoutButton in this check because buttons are implemented
+    // using flex box but should still support first-line|first-letter.
+    // The flex box and grid specs require that flex box and grid do not
+    // support first-line|first-letter, though.
+    // TODO(cbiesinger): Remove when buttons are implemented with align-items instead
+    // of flex box. crbug.com/226252.
+    bool canHaveFirstLineOrFirstLetterStyle() const { return isLayoutBlockFlow() || isLayoutButton(); }
+
     // This function returns the containing block of the object.
     // Due to CSS being inconsistent, a containing block can be a relatively
     // positioned inline, thus we can't return a LayoutBlock from this function.