Invalidate first line display item clients when first line style changes

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

Index: third_party/WebKit/Source/core/layout/LayoutBlock.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutBlock.cpp b/third_party/WebKit/Source/core/layout/LayoutBlock.cpp
index 0a7572f7a7f0e4aa2ec4a84f2e3f2b828c1c6118..366fb79d603394a3717f7efa2a5cbfe3d0819f32 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBlock.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutBlock.cpp
@@ -2296,18 +2296,7 @@ int LayoutBlock::inlineBlockBaseline(LineDirectionMode lineDirection) const
     return -1;
 }
 
-static inline bool isLayoutBlockFlowOrLayoutButton(LayoutObject* layoutObject)
-{
-    // 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.
-    // FIXME: Remove when buttons are implemented with align-items instead
-    // of flex box.
-    return layoutObject->isLayoutBlockFlow() || layoutObject->isLayoutButton();
-}
-
-LayoutBlock* LayoutBlock::firstLineBlock() const
+LayoutBlock* LayoutBlock::firstLineStyleBlock() const
 {
     LayoutBlock* firstLineBlock = const_cast<LayoutBlock*>(this);
     bool hasPseudo = false;
@@ -2318,7 +2307,7 @@ LayoutBlock* LayoutBlock::firstLineBlock() const
         LayoutObject* parentBlock = firstLineBlock->parent();
         if (firstLineBlock->isReplaced() || firstLineBlock->isFloatingOrOutOfFlowPositioned()
             || !parentBlock
-            || !isLayoutBlockFlowOrLayoutButton(parentBlock))
+            || !parentBlock->canHaveFirstLineOrFirstLetterStyle())
             break;
         ASSERT_WITH_SECURITY_IMPLICATION(parentBlock->isLayoutBlock());
         if (toLayoutBlock(parentBlock)->firstChild() != firstLineBlock)
@@ -2332,6 +2321,15 @@ LayoutBlock* LayoutBlock::firstLineBlock() const
     return firstLineBlock;
 }
 
+LayoutBlockFlow* LayoutBlock::firstLineContainer() const
+{
+    for (LayoutObject* child = firstChild(); child && !child->isFloatingOrOutOfFlowPositioned() && child->isLayoutBlockFlow(); child = toLayoutBlock(child)->firstChild()) {
+        if (child->childrenInline())
+            return toLayoutBlockFlow(child);
+    }
+    return nullptr;
+}
+
 // Helper methods for obtaining the last line, computing line counts and heights for line counts
 // (crawling into blocks).
 static bool shouldCheckLines(LayoutObject* obj)