Cleanup: Pass std::string as const reference if possible

chrome/common/icon_with_badge_image_source.cc

 // 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.
 
 #include "chrome/common/icon_with_badge_image_source.h"
 
 #include <algorithm>
 
 #include "chrome/common/badge_util.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/image/image_skia_operations.h"
 
-IconWithBadgeImageSource::Badge::Badge(std::string text,
+IconWithBadgeImageSource::Badge::Badge(const std::string& text,
                                        SkColor text_color,
                                        SkColor background_color)
-    : text(text), text_color(text_color), background_color(background_color) {
-}
+    : text(text), text_color(text_color), background_color(background_color) {}
 
 IconWithBadgeImageSource::Badge::~Badge() {}
 
 IconWithBadgeImageSource::IconWithBadgeImageSource(const gfx::Size& size)
     : gfx::CanvasImageSource(size, false),
       grayscale_(false),
       paint_decoration_(false) {
 }
 
 IconWithBadgeImageSource::~IconWithBadgeImageSource() {
@@ skipping 44 matching lines @@
   paint.setXfermodeMode(SkXfermode::kSrc_Mode);
   canvas->DrawCircle(center_point,
                      major_radius,
                      paint);
   paint.setColor(decoration_color);
   canvas->DrawCircle(center_point,
                      minor_radius,
                      paint);
 }