Invalidate first line display item clients when first line style changes

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 d18a8bdfec657ca4677d650192fcf9a19d44e955..ff366cd2570eae7e854f1094a13c67f6d22a8fc7 100644
--- a/third_party/WebKit/Source/core/layout/LayoutObject.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutObject.cpp
@@ -1845,12 +1845,23 @@ void LayoutObject::setPseudoStyle(PassRefPtr<ComputedStyle> pseudoStyle)
 void LayoutObject::firstLineStyleDidChange(const ComputedStyle& oldStyle, const ComputedStyle& newStyle)
 {
     StyleDifference diff = oldStyle.visualInvalidationDiff(newStyle);
-    if (diff.hasDifference()) {
-        // TODO(rune@opera.com): We should use the diff to determine whether a repaint vs. layout
-        // is needed, but for now just assume a layout will be required. The diff code
-        // in LayoutObject::setStyle would need to be factored out so that it could be reused.
-        setNeedsLayoutAndPrefWidthsRecalcAndFullPaintInvalidation(LayoutInvalidationReason::StyleChange);
+
+    if (diff.needsPaintInvalidation() || diff.textDecorationOrColorChanged()) {
+        LayoutBlock* block = nullptr;
+        if (isLayoutBlockFlow() || isLayoutButton()) {
+            block = toLayoutBlock(this);
+        } else if (isLayoutInline()) {
+            if (toLayoutInline(this)->firstLineBoxIncludingCulling()->isFirstLineStyle())

[mstensho (USE GERRIT), 2015/12/02 10:09:31]

Can't firstLineBoxIncludingCulling() return nullptr?

[Xianzhu, 2015/12/02 17:41:57]

Not sure though didn't encounter. Added nullptr checking.

+                block = containingBlock();
+        }
+        if (block) {
+            block->invalidateDisplayItemClientsOfFirstLine();
+            if (!RuntimeEnabledFeatures::slimmingPaintV2Enabled())
+                block->setShouldDoFullPaintInvalidation();
+        }
     }
+    if (diff.needsLayout())
+        setNeedsLayoutAndPrefWidthsRecalc(LayoutInvalidationReason::StyleChange);
 }
 
 void LayoutObject::markContainingBlocksForOverflowRecalc()