PrintPreview: Remove |page_number| from StartPageForVectorCanvas function.

printing/metafile.h

Index: printing/metafile.h
diff --git a/printing/metafile.h b/printing/metafile.h
index dbb838cc2aa64f5d3bea67412cb894dce79c5648..84c0556c52999e0a2c8b907e7952a25c95b2b004 100644
--- a/printing/metafile.h
+++ b/printing/metafile.h
@@ -53,9 +53,8 @@ class Metafile {
 
   // This method calls StartPage and then returns an appropriate
   // VectorPlatformDevice implementation bound to the context created by
-  // StartPage or NULL on error. |page_number| is zero based.
+  // StartPage or NULL on error.
   virtual SkDevice* StartPageForVectorCanvas(
-      int page_number,
       const gfx::Size& page_size,
       const gfx::Rect& content_area,
       const float& scale_factor) = 0;