Optimize outline paint invalidation

third_party/WebKit/Source/core/paint/ObjectPaintInvalidator.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/paint/ObjectPaintInvalidator.h"
 
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/layout/LayoutView.h"
 #include "core/layout/api/LayoutPartItem.h"
@@ skipping 470 matching lines @@
 
   if (m_context.oldVisualRect.isEmpty() && m_context.newVisualRect.isEmpty())
     return PaintInvalidationNone;
 
   if (backgroundObscurationChanged)
     return PaintInvalidationBackgroundObscurationChange;
 
   if (m_object.paintedOutputOfObjectHasNoEffectRegardlessOfSize())
     return PaintInvalidationNone;
 
-  const ComputedStyle& style = m_object.styleRef();
-
   // The outline may change shape because of position change of descendants. For
   // simplicity, just force full paint invalidation if this object is marked for

[chrishtr, 2017/02/03 02:00:11]

Comment needs updating.

[Xianzhu, 2017/02/03 04:38:35]

Done.

   // checking paint invalidation for any reason.
-  // TODO(wangxianzhu): Optimize this.
-  if (style.hasOutline())
+  if (m_object.outlineMayBeAffectedByDescendants() ||
+      m_object.previousOutlineMayBeAffectedByDescendants()) {
+    m_object.getMutableForPainting()
+        .updatePreviousOutlineMayBeAffectedByDescendants();
     return PaintInvalidationOutline;
+  }
 
   // If the size is zero on one of our bounds then we know we're going to have
   // to do a full invalidation of either old bounds or new bounds.
   if (m_context.oldVisualRect.isEmpty())
     return PaintInvalidationBecameVisible;
   if (m_context.newVisualRect.isEmpty())
     return PaintInvalidationBecameInvisible;
 
   // If we shifted, we don't know the exact reason so we are conservative and
   // trigger a full invalidation. Shifting could be caused by some layout
@@ skipping 95 matching lines @@
 
   m_context.paintingLayer->setNeedsRepaint();
   m_object.invalidateDisplayItemClients(reason);
   return reason;
 }
 
 DisablePaintInvalidationStateAsserts::DisablePaintInvalidationStateAsserts()
     : m_disabler(&gDisablePaintInvalidationStateAsserts, true) {}
 
 }  // namespace blink