[Coverity] Pass-by-ref instead of pass-by-val

chrome/browser/favicon/select_favicon_frames.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/browser/favicon/select_favicon_frames.h"
 
 #include "skia/ext/image_operations.h"
 #include "ui/gfx/image/image.h"
 #include "ui/gfx/image/image_skia.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 
 namespace {
 
 size_t BiggestCandidate(const std::vector<SkBitmap>& bitmaps) {
   size_t max_index = 0;
   int max_area = bitmaps[0].width() * bitmaps[0].height();
   for (size_t i = 1; i < bitmaps.size(); ++i) {
     int area = bitmaps[i].width() * bitmaps[i].height();
     if (area > max_area) {
       max_area = area;
       max_index = i;
     }
   }
   return max_index;
 }
 
-SkBitmap PadWithBorder(SkBitmap contents, int desired_size, int source_size) {
+SkBitmap PadWithBorder(const SkBitmap& contents,

[Nico, 2012/09/19 10:29:16]

SkBitmaps are refcounted and by design very cheap to copy. We rely on this
property in many places. I intentionally didn't pass them by ref. (Not that
doing it hurts much either, but it's more code and unnecessary.)

[sky, 2012/09/19 14:25:05]

We should still pass by ref if possible.

+                       int desired_size,
+                       int source_size) {
   SkBitmap bitmap;
   bitmap.setConfig(
       SkBitmap::kARGB_8888_Config, desired_size, desired_size);
   bitmap.allocPixels();
   bitmap.eraseARGB(0, 0, 0, 0);
 
   {
     SkCanvas canvas(bitmap);
     int shift = (desired_size - source_size) / 2;
     SkRect dest(SkRect::MakeXYWH(shift, shift, source_size, source_size));
     canvas.drawBitmapRect(contents, NULL, dest);
   }
 
   return bitmap;
 }
 
-SkBitmap SampleNearestNeighbor(SkBitmap contents, int desired_size) {
+SkBitmap SampleNearestNeighbor(const SkBitmap& contents, int desired_size) {
   SkBitmap bitmap;
   bitmap.setConfig(
       SkBitmap::kARGB_8888_Config, desired_size, desired_size);
   bitmap.allocPixels();
   if (!contents.isOpaque())
     bitmap.eraseARGB(0, 0, 0, 0);
 
   {
     SkCanvas canvas(bitmap);
     SkRect dest(SkRect::MakeWH(desired_size, desired_size));
@@ skipping 84 matching lines @@
   }
 
   for (size_t i = 0; i < scale_factors.size(); ++i) {
     multi_image.AddRepresentation(gfx::ImageSkiaRep(
           SelectCandidate(bitmaps, desired_size, scale_factors[i]),
           scale_factors[i]));
   }
 
   return multi_image;
 }