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 e1ab0f869ed6606ca262ca9650157a4c85e83ece..2d5b99f6f472c8081a71bf0f9b58daad976d56d2 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->partialLayout().isStopping())
+        return;
+
     if (hasRenderNamedFlowThreads())
         flowThreadController()->layoutRenderNamedFlowThreads();
+
 #ifndef NDEBUG
     checkLayoutState(state);
 #endif
@@ -212,6 +217,11 @@ bool RenderView::initializeLayoutState(LayoutState& state)
 // as detected in the previous step.
 void RenderView::layoutContentInAutoLogicalHeightRegions(const LayoutState& state)
 {
+    if (!m_frameView->partialLayout().isStopping()) {
+        // Disable partial layout for any two-pass layout algorithm.
+        m_frameView->partialLayout().reset();
+    }
+
     // 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()) {
@@ -280,6 +290,11 @@ void RenderView::layout()
     else
         layoutContent(state);
 
+    if (m_frameView->partialLayout().isStopping()) {
+        m_layoutState = 0;
+        return;
+    }
+
 #ifndef NDEBUG
     checkLayoutState(state);
 #endif