107656 2013-01-23 03:10:56 -0800 Coordinated Graphics: CoordinatedLayerTreeHost::sizeDidChange uses the size in css unit, not device unit. 2013-03-10 20:01:43 -0700 1 1 1 Unclassified WebKit Layout and Rendering 528+ (Nightly build) Unspecified Unspecified RESOLVED INVALID P2 Normal --- 105978 103105 1 dongseong.hwang webkit-unassigned oldest_to_newest 814062 0 dongseong.hwang 2013-01-23 03:10:56 -0800 CoordinatedLayerTreeHost::sizeDidChange set the size of WebPage to GraphicsLayer, and the size is in device units. void CoordinatedLayerTreeHost::sizeDidChange(const WebCore::IntSize& newSize) { if (m_rootLayer->size() == newSize) return; m_rootLayer->setSize(newSize); // If the newSize exposes new areas of the non-composited content a setNeedsDisplay is needed // for those newly exposed areas. FloatSize oldSize = m_nonCompositedContentLayer->size(); m_nonCompositedContentLayer->setSize(newSize); ... } But all other child layer has the size in css unit. I don't find any artifact yet, because TBS paints entire contents for non composited layer. But it is a potential bug. In addition, I'm not sure if WebPage should use the size in device unit. 814084 1 dongseong.hwang 2013-01-23 03:56:31 -0800 I think it may be related to Bug 104906 852024 2 dongseong.hwang 2013-03-10 20:01:43 -0700 Bug 111407 works in progress about refactoring CoordinatedLayerTreeHost::sizeDidChange.