Move LayoutObject::m_previousPosition... into a global map in ObjectPaintInvalidator

third_party/WebKit/Source/core/layout/LayoutObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2011 Apple Inc.
  *               All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved.
  *               (http://www.torchmobile.com/)
@@ skipping 109 matching lines @@
 struct SameSizeAsLayoutObject : DisplayItemClient {
   virtual ~SameSizeAsLayoutObject() {}  // Allocate vtable pointer.
   void* pointers[5];
   Member<void*> members[1];
 #if ENABLE(ASSERT)
   unsigned m_debugBitfields : 2;
 #endif
   unsigned m_bitfields;
   unsigned m_bitfields2;
   LayoutRect m_previousVisualRect;
-  LayoutPoint m_previousPosition;
 };
 
 static_assert(sizeof(LayoutObject) == sizeof(SameSizeAsLayoutObject),
               "LayoutObject should stay small");
 
 bool LayoutObject::s_affectsParentBlock = false;
 
 // The pointer to paint properties is implemented as a global hash map
 // temporarily, to avoid memory regression during the transition towards SPv2.
 typedef HashMap<const LayoutObject*, std::unique_ptr<ObjectPaintProperties>>
@@ skipping 1056 matching lines @@
   LayoutView* v = view();
   if (v->document().printing())
     return PaintInvalidationNone;  // Don't invalidate paints if we're printing.
 
   PaintInvalidatorContextAdapter context(paintInvalidationState);
 
   const LayoutBoxModelObject& paintInvalidationContainer =
       paintInvalidationState.paintInvalidationContainer();
   DCHECK(paintInvalidationContainer == containerForPaintInvalidation());
 
+  ObjectPaintInvalidator paintInvalidator(*this);
   context.oldVisualRect = previousVisualRect();
-  context.oldLocation = previousPositionFromPaintInvalidationBacking();
+  context.oldLocation = paintInvalidator.previousLocationInBacking();
   context.newVisualRect = paintInvalidationState.computeVisualRectInBacking();
-  context.newLocation =
-      paintInvalidationState.computePositionFromPaintInvalidationBacking();
+  // Use visual rect location for LayoutTexts and non-container SVG objects
+  // because visual rect change suffices to detect layout caused invalidation.
+  context.newLocation = !isBoxModelObject() && !isSVGContainer()

[chrishtr, 2016/11/04 18:20:06]

You don't need a conditional here I think.
paintInvalidationState.computeLocationInBacking already does
the conditional for you.

[Xianzhu, 2016/11/04 19:11:03]

They are in different paths (PaintInvalidator path vs PaintInvalidationState
path). Now put the check into
PaintInvalidationState::computePreviousLocationInBacking().

+                            ? context.newVisualRect.location()
+                            : paintInvalidationState.computeLocationInBacking();
 
   IntSize adjustment =
       scrollAdjustmentForPaintInvalidation(paintInvalidationContainer);
   context.newLocation.move(adjustment);
   context.newVisualRect.move(adjustment);
 
   adjustVisualRectForRasterEffects(context.newVisualRect);
 
   setPreviousVisualRect(context.newVisualRect);
-  setPreviousPositionFromPaintInvalidationBacking(context.newLocation);
+  paintInvalidator.setPreviousLocationInBacking(context.newLocation);
 
   if (!shouldCheckForPaintInvalidationRegardlessOfPaintInvalidationState() &&
       paintInvalidationState
           .forcedSubtreeInvalidationRectUpdateWithinContainerOnly()) {
     // We are done updating the visual rect. No other paint invalidation work
     // to do for this object.
     return PaintInvalidationNone;
   }
 
   return invalidatePaintIfNeeded(context);
@@ skipping 2314 matching lines @@
     const blink::LayoutObject* root = object1;
     while (root->parent())
       root = root->parent();
     root->showLayoutTreeAndMark(object1, "*", object2, "-", 0);
   } else {
     WTFLogAlways("%s", "Cannot showLayoutTree. Root is (nil)");
   }
 }
 
 #endif