Relayout if FrameView::updateViewSize() set needsLayout

third_party/WebKit/Source/core/frame/FrameView.cpp

Index: third_party/WebKit/Source/core/frame/FrameView.cpp
diff --git a/third_party/WebKit/Source/core/frame/FrameView.cpp b/third_party/WebKit/Source/core/frame/FrameView.cpp
index f881a6042a874b94b9ee6295408a6c25b0d0dcb8..f5424abb836cbe0d89adb391899301cf66f2a0a4 100644
--- a/third_party/WebKit/Source/core/frame/FrameView.cpp
+++ b/third_party/WebKit/Source/core/frame/FrameView.cpp
@@ -161,6 +161,7 @@ FrameView::FrameView(LocalFrame* frame)
     , m_isUpdatingAllLifecyclePhases(false)
     , m_scrollAnchor(this)
     , m_needsScrollbarsUpdate(false)
+    , m_suppressAdjustViewSize(false)
 {
     ASSERT(m_frame);
     init();
@@ -531,6 +532,9 @@ void FrameView::setContentsSize(const IntSize& size)
 
 void FrameView::adjustViewSize()
 {
+    if (m_suppressAdjustViewSize)
+        return;
+
     LayoutViewItem layoutViewItem = this->layoutViewItem();
     if (layoutViewItem.isNull())
         return;
@@ -553,6 +557,15 @@ void FrameView::adjustViewSize()
     setContentsSize(size);
 }
 
+void FrameView::adjustViewSizeAndLayout()
+{
+    adjustViewSize();
+    if (needsLayout()) {
+        TemporaryChange<bool> suppressAdjustViewSize(m_suppressAdjustViewSize, true);
+        layout();
+    }
+}
+
 void FrameView::calculateScrollbarModesFromOverflowStyle(const ComputedStyle* style, ScrollbarMode& hMode, ScrollbarMode& vMode)
 {
     hMode = vMode = ScrollbarAuto;
@@ -1040,7 +1053,7 @@ void FrameView::layout()
     } // Reset m_layoutSchedulingEnabled to its previous value.
 
     if (!inSubtreeLayout && !document->printing())

[szager1, 2016/06/01 07:48:57]

Can you make adjustViewSizeAndLayout return a bool indicating whether it
actually ran layout, and add an early return here?  Like this:

if (!inSubtreeLayout && !document->printing() && adjustViewSizeAndLayout()
  return;

Without this change, the rest of the code in layout() will redundantly run
twice.

-        adjustViewSize();
+        adjustViewSizeAndLayout();
 
     m_frameTimingRequestsDirty = true;
 
@@ -2773,7 +2786,7 @@ void FrameView::forceLayoutForPagination(const FloatSize& pageSize, const FloatS
         }
     }
 
-    adjustViewSize();
+    adjustViewSizeAndLayout();
 }
 
 IntRect FrameView::convertFromLayoutObject(const LayoutObject& layoutObject, const IntRect& layoutObjectRect) const