Less code duplication in PaintLayer::collectFragments()

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

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights
  * reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
@@ skipping 1540 matching lines @@
     PaintLayerFragments& fragments,
     const PaintLayer* rootLayer,
     const LayoutRect& dirtyRect,
     ClipRectsCacheSlot clipRectsCacheSlot,
     PaintLayer::GeometryMapperOption geometryMapperOption,
     OverlayScrollbarClipBehavior overlayScrollbarClipBehavior,
     ShouldRespectOverflowClipType respectOverflowClip,
     const LayoutPoint* offsetFromRoot,
     const LayoutSize& subPixelAccumulation,
     const LayoutRect* layerBoundingBox) {
-  if (!enclosingPaginationLayer()) {
-    // For unpaginated layers, there is only one fragment.
+  // For unpaginated layers, there is only one fragment. We also avoid
+  // fragmentation when compositing, due to implementation limitations.
+  if (!enclosingPaginationLayer() ||
+      !shouldFragmentCompositedBounds(rootLayer)) {
     appendSingleFragmentIgnoringPagination(
         fragments, rootLayer, dirtyRect, clipRectsCacheSlot,
         geometryMapperOption, overlayScrollbarClipBehavior, respectOverflowClip,
-        offsetFromRoot, subPixelAccumulation);
-    return;
-  }
-
-  if (!shouldFragmentCompositedBounds(rootLayer)) {
-    appendSingleFragmentIgnoringPagination(
-        fragments, rootLayer, dirtyRect, clipRectsCacheSlot,
-        geometryMapperOption, overlayScrollbarClipBehavior, respectOverflowClip,
         offsetFromRoot, subPixelAccumulation);
     return;
   }
 
   // Compute our offset within the enclosing pagination layer.
   LayoutPoint offsetWithinPaginatedLayer;
   convertToLayerCoords(enclosingPaginationLayer(), offsetWithinPaginatedLayer);
 
   // Calculate clip rects relative to the enclosingPaginationLayer. The purpose
   // of this call is to determine our bounds clipped to intermediate layers
@@ skipping 1634 matching lines @@
 }
 
 void showLayerTree(const blink::LayoutObject* layoutObject) {
   if (!layoutObject) {
     LOG(INFO) << "Cannot showLayerTree. Root is (nil)";
     return;
   }
   showLayerTree(layoutObject->enclosingLayer());
 }
 #endif