Tweak priorities of paint invalidation reasons

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

 // 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.
 
 #ifndef ObjectPaintInvalidator_h
 #define ObjectPaintInvalidator_h
 
 #include "platform/graphics/PaintInvalidationReason.h"
 #include "wtf/Allocator.h"
 
 namespace blink {
 
 class LayoutObject;
 class LayoutRect;
 struct PaintInvalidatorContext;
 
 class ObjectPaintInvalidator {
     STACK_ALLOCATED();
 public:
     ObjectPaintInvalidator(const LayoutObject& object, const PaintInvalidatorContext& context)
         : m_object(object), m_context(context) { }
 
     static void objectWillBeDestroyed(const LayoutObject&);
 
     PaintInvalidationReason invalidatePaintIfNeeded() { return invalidatePaintIfNeededWithComputedReason(computePaintInvalidationReason()); }
 
     PaintInvalidationReason computePaintInvalidationReason();
     PaintInvalidationReason invalidatePaintIfNeededWithComputedReason(PaintInvalidationReason);
 
-private:
-    void invalidateSelectionIfNeeded(PaintInvalidationReason);
-
     // This function tries to minimize the amount of invalidation generated by invalidating the "difference" between
     // |m_context.oldBounds| and |m_context.newBounds|. This means invalidating the union of the previous rectangles
     // but not their intersection. The use case is when an element only requires a paint invalidation (which means
     // that its content didn't change) and its bounds changed but its location didn't.
     // If we don't meet the criteria for an incremental paint, the alternative is a full paint invalidation.
-    void incrementallyInvalidatePaint();
+    // Returns true if any paint invalidation is done.
+    bool incrementallyInvalidatePaint();
+
+private:
+    void invalidateSelectionIfNeeded(PaintInvalidationReason);
 
     // This function generates a full invalidation, which means invalidating both |oldBounds| and |newBounds|.
     // This is the default choice when generating an invalidation, as it is always correct, albeit it may force some extra painting.
     void fullyInvalidatePaint(PaintInvalidationReason, const LayoutRect& oldBounds, const LayoutRect& newBounds);
 
     const LayoutObject& m_object;
     const PaintInvalidatorContext& m_context;
 };
 
 } // namespace blink
 
 #endif