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..b7c4b85f5e3f6091644fb148fe3d1feab7aedcda 100644
--- a/third_party/WebKit/Source/core/layout/LayoutObject.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutObject.cpp
@@ -1845,12 +1845,24 @@ 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()) {
+        LayoutBlockFlow* block = nullptr;
+        if (isLayoutBlockFlow()) {
+            block = toLayoutBlockFlow(this);
+        } else {
+            ASSERT(isLayoutInline());
+            if (toLayoutInline(this)->firstLineBoxIncludingCulling()->isFirstLineStyle())
+                block = toLayoutBlockFlow(containingBlock());
+        }
+        if (block) {
+            block->invalidateDisplayItemClientsOfFirstLine();
+            if (!RuntimeEnabledFeatures::slimmingPaintV2Enabled())
+                block->setShouldDoFullPaintInvalidation();

[Xianzhu, 2015/12/01 20:06:25]

This is needed for rect-based invalidation. Currently this over-invalidates.
Will switch to use display item client bounds for slimming paint v2.

+        }
     }
+    if (diff.needsLayout())
+        setNeedsLayoutAndPrefWidthsRecalc(LayoutInvalidationReason::StyleChange);
 }
 
 void LayoutObject::markContainingBlocksForOverflowRecalc()