Initial containing block for print not affected by page zoom.

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 85977cb686099cde2a01bc2b4e1861dcc3e901cb..c911d78173efad9517a47b0c14fc79342b03dae4 100644
--- a/third_party/WebKit/Source/core/frame/FrameView.cpp
+++ b/third_party/WebKit/Source/core/frame/FrameView.cpp
@@ -1405,7 +1405,9 @@ IntRect FrameView::computeVisibleArea() {
 }
 
 FloatSize FrameView::viewportSizeForViewportUnits() const {
-  float zoom = frame().pageZoomFactor();
+  float zoom = 1;
+  if (!m_frame->document() || !m_frame->document()->printing())
+    zoom = frame().pageZoomFactor();
 
   LayoutViewItem layoutViewItem = this->layoutViewItem();
   if (layoutViewItem.isNull())
@@ -1435,6 +1437,13 @@ FloatSize FrameView::viewportSizeForViewportUnits() const {
   return layoutSize;
 }
 
+FloatSize FrameView::viewportSizeForMediaQueries() const {
+  FloatSize viewportSize(layoutSize(IncludeScrollbars));
+  if (!m_frame->document() || !m_frame->document()->printing())
+    viewportSize.scale(1 / frame().pageZoomFactor());
+  return viewportSize;
+}
+
 DocumentLifecycle& FrameView::lifecycle() const {
   DCHECK(m_frame);
   DCHECK(m_frame->document());