Fix print preview clipping issues due to scaling.

printing/metafile.h

Index: printing/metafile.h
===================================================================
--- printing/metafile.h	(revision 83537)
+++ printing/metafile.h	(working copy)
@@ -57,14 +57,15 @@
   // VectorPlatformDevice implementation bound to the context created by
   // StartPage or NULL on error.
   virtual skia::PlatformDevice* StartPageForVectorCanvas(
-      const gfx::Size& page_size, const gfx::Point& content_origin,
+      const gfx::Size& page_size,
+      const gfx::Rect& content_area,
       const float& scale_factor) = 0;
 
-  // Prepares a context for rendering a new page at the specified
-  // |content_origin| with the given |page_size| and a |scale_factor| to use for
-  // the drawing. The units are in points (=1/72 in). Returns true on success.
+  // Prepares a context for rendering a new page with the given |page_size|,
+  // |content_area| and  a |scale_factor| to use for the drawing. The units are
+  // in points (=1/72 in). Returns true on success.
   virtual bool StartPage(const gfx::Size& page_size,
-                         const gfx::Point& content_origin,
+                         const gfx::Rect& content_area,
                          const float& scale_factor) = 0;
 
   // Closes the current page and destroys the context used in rendering that