First step of PaintInvalidator implementation

third_party/WebKit/Source/core/paint/SVGModelObjectPaintInvalidator.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/SVGModelObjectPaintInvalidator.h"
+
+#include "core/layout/svg/LayoutSVGModelObject.h"
+#include "core/paint/ObjectPaintInvalidator.h"
+
+namespace blink {
+
+PaintInvalidationReason SVGModelObjectPaintInvalidator::invalidatePaintIfNeeded()
+{
+    PaintInvalidationReason reason = ObjectPaintInvalidator(m_object, m_context).computePaintInvalidationReason();
+
+    // Disable incremental invalidation for SVG objects to prevent under-
+    // invalidation. Unlike boxes, it is non-trivial (and rare) for SVG objects
+    // to be able to be incrementally invalidated (e.g., on height changes).
+    if (reason == PaintInvalidationIncremental)
+        reason = PaintInvalidationFull;
+
+    return ObjectPaintInvalidator(m_object, m_context).invalidatePaintIfNeededWithComputedReason(reason);
+}
+
+} // namespace blink