Initial viewport is not the same as FrameView rect.

third_party/WebKit/Source/core/css/MediaValuesInitialViewport.cpp

Index: third_party/WebKit/Source/core/css/MediaValuesInitialViewport.cpp
diff --git a/third_party/WebKit/Source/core/css/MediaValuesInitialViewport.cpp b/third_party/WebKit/Source/core/css/MediaValuesInitialViewport.cpp
index 0d9f776cd3dc65b6f77ac90dee16ac14a5c683db..8ed02280cdb46f52ffe8f4cdb89aaab0578e15b6 100644
--- a/third_party/WebKit/Source/core/css/MediaValuesInitialViewport.cpp
+++ b/third_party/WebKit/Source/core/css/MediaValuesInitialViewport.cpp
@@ -19,17 +19,13 @@ MediaValuesInitialViewport::MediaValuesInitialViewport(LocalFrame& frame)
     : MediaValuesDynamic(&frame) {}
 
 double MediaValuesInitialViewport::viewportWidth() const {
-  DCHECK(m_frame->view() && m_frame->document());
-  int viewportWidth = m_frame->view()->frameRect().width();
-  return adjustDoubleForAbsoluteZoom(
-      viewportWidth, m_frame->document()->layoutViewItem().styleRef());
+  DCHECK(m_frame->view());
+  return m_frame->view()->initialViewportWidth();
 }
 
 double MediaValuesInitialViewport::viewportHeight() const {
-  DCHECK(m_frame->view() && m_frame->document());
-  int viewportHeight = m_frame->view()->frameRect().height();
-  return adjustDoubleForAbsoluteZoom(
-      viewportHeight, m_frame->document()->layoutViewItem().styleRef());
+  DCHECK(m_frame->view());
+  return m_frame->view()->initialViewportHeight();
 }
 
 }  // namespace blink