Add infrastructure for partial layouts

Source/core/rendering/RenderView.cpp

Index: Source/core/rendering/RenderView.cpp
diff --git a/Source/core/rendering/RenderView.cpp b/Source/core/rendering/RenderView.cpp
index 105eadd08bcf1e2afe1a9e89aae42729dc9213e0..c40eaa5548c843e287a05f35fabb6b99f754db5d 100644
--- a/Source/core/rendering/RenderView.cpp
+++ b/Source/core/rendering/RenderView.cpp
@@ -120,8 +120,13 @@ void RenderView::layoutContent(const LayoutState& state)
     ASSERT(needsLayout());
 
     RenderBlock::layout();
+
+    if (m_frameView->shouldStopPartialLayout())
+        return;
+
     if (hasRenderNamedFlowThreads())
         flowThreadController()->layoutRenderNamedFlowThreads();
+
 #ifndef NDEBUG
     checkLayoutState(state);
 #endif
@@ -214,6 +219,11 @@ bool RenderView::initializeLayoutState(LayoutState& state)
 // as detected in the previous step.
 void RenderView::layoutContentInAutoLogicalHeightRegions(const LayoutState& state)
 {
+    if (!m_frameView->shouldStopPartialLayout()) {
+        // disable partial layout for any two-pass layout algorithm.
+        m_frameView->resetPartialLayoutState();
+    }
+
     // We need to invalidate all the flows with auto-height regions if one such flow needs layout.
     // If none is found we do a layout a check back again afterwards.
     if (!flowThreadController()->updateFlowThreadsNeedingLayout()) {
@@ -283,6 +293,11 @@ void RenderView::layout()
     else
         layoutContent(state);
 
+    if (m_frameView->shouldStopPartialLayout()) {
+        m_layoutState = 0;
+        return;
+    }
+
 #ifndef NDEBUG
     checkLayoutState(state);
 #endif