Compute pageScaleFactor on page so that fixed layout page fits width of window.

content/renderer/render_view_impl.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_RENDERER_RENDER_VIEW_IMPL_H_
 #define CONTENT_RENDERER_RENDER_VIEW_IMPL_H_
 #pragma once
 
 #include <deque>
 #include <map>
@@ skipping 994 matching lines @@
   // scroll bars on windows smaller than this size.  Used for windows that the
   // browser resizes to the size of the content, such as browser action popups.
   // If a render view is set to the minimum size of its content, webkit may add
   // scroll bars.  This makes sense for fixed sized windows, but it does not
   // make sense when the size of the view was chosen to fit the content.
   // This setting ensures that no scroll bars are drawn.  The size limit exists
   // because if the view grows beyond a size known to the browser, scroll bars
   // should be drawn.
   gfx::Size disable_scrollbars_size_limit_;
 
+  int default_device_scale_factor_;
+
   // Loading state -------------------------------------------------------------
 
   // True if the top level frame is currently being loaded.
   bool is_loading_;
 
   // The gesture that initiated the current navigation.
   NavigationGesture navigation_gesture_;
 
   // Used for popups.
   bool opened_by_user_gesture_;
@@ skipping 253 matching lines @@
   // bunch of stuff, you should probably create a helper class and put your
   // data and methods on that to avoid bloating RenderView more.  You can
   // use the Observer interface to filter IPC messages and receive frame change
   // notifications.
   // ---------------------------------------------------------------------------
 
   DISALLOW_COPY_AND_ASSIGN(RenderViewImpl);
 };
 
 #endif  // CONTENT_RENDERER_RENDER_VIEW_IMPL_H_