Fix some nits from r447440.

printing/pdf_render_settings.h

 // Copyright (c) 2011 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 PRINTING_PDF_RENDER_SETTINGS_H_
 #define PRINTING_PDF_RENDER_SETTINGS_H_
 
 #include "build/build_config.h"
 #include "ui/gfx/geometry/point.h"
 #include "ui/gfx/geometry/rect.h"
 
 namespace printing {
 
 // Defining PDF rendering settings.
 struct PdfRenderSettings {
   enum Mode {
     NORMAL = 0,
 #if defined(OS_WIN)
     GDI_TEXT,
     POSTSCRIPT_LEVEL2,
     POSTSCRIPT_LEVEL3,
     LAST = POSTSCRIPT_LEVEL3,
 #else
     LAST = NORMAL,
 #endif
   };
 
   PdfRenderSettings() : dpi(0), autorotate(false), mode(Mode::NORMAL) {}
-  PdfRenderSettings(gfx::Rect area,
-                    gfx::Point offsets,
+  PdfRenderSettings(const gfx::Rect& area,
+                    const gfx::Point& offsets,
                     int dpi,
                     bool autorotate,
                     Mode mode)
       : area(area),
         offsets(offsets),
         dpi(dpi),
         autorotate(autorotate),
         mode(mode) {}
   ~PdfRenderSettings() {}
 
   gfx::Rect area;
   gfx::Point offsets;
   int dpi;
   bool autorotate;
   Mode mode;
 };
 
 }  // namespace printing
 
 #endif  // PRINTING_PDF_RENDER_SETTINGS_H_