Fixed pass-by-value to pass-by-reference

chrome/browser/tab_contents/thumbnail_generator.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/tab_contents/thumbnail_generator.h"
 
 #include <algorithm>
 #include <map>
 
 #include "base/bind.h"
@@ skipping 357 matching lines @@
     if (iterator->second->renderer == renderer) {
       ThumbnailCallbackMap::iterator nuked = iterator;
       ++iterator;
       callback_map_.erase(nuked);
       continue;
     }
     ++iterator;
   }
 }
 
-double ThumbnailGenerator::CalculateBoringScore(SkBitmap* bitmap) {
-  if (bitmap->isNull() || bitmap->empty())
+double ThumbnailGenerator::CalculateBoringScore(const SkBitmap& bitmap) {
+  if (bitmap.isNull() || bitmap.empty())
     return 1.0;
   int histogram[256] = {0};
   color_utils::BuildLumaHistogram(bitmap, histogram);
 
   int color_count = *std::max_element(histogram, histogram + 256);
-  int pixel_count = bitmap->width() * bitmap->height();
+  int pixel_count = bitmap.width() * bitmap.height();
   return static_cast<double>(color_count) / pixel_count;
 }
 
 SkBitmap ThumbnailGenerator::GetClippedBitmap(const SkBitmap& bitmap,
                                               int desired_width,
                                               int desired_height,
                                               ClipResult* clip_result) {
   const SkRect dest_rect = { 0, 0,
                              SkIntToScalar(desired_width),
                              SkIntToScalar(desired_height) };
@@ skipping 54 matching lines @@
   SkBitmap thumbnail = GetThumbnailForRendererWithOptions(
       web_contents->GetRenderViewHost(), options, &clip_result);
   // Failed to generate a thumbnail. Maybe the tab is in the background?
   if (thumbnail.isNull())
     return;
 
   UpdateThumbnail(web_contents, thumbnail, clip_result);
 }
 
 void ThumbnailGenerator::UpdateThumbnail(
-    WebContents* web_contents, SkBitmap thumbnail,
+    WebContents* web_contents, const SkBitmap& thumbnail,
     const ThumbnailGenerator::ClipResult& clip_result) {
 
   Profile* profile =
       Profile::FromBrowserContext(web_contents->GetBrowserContext());
   history::TopSites* top_sites = profile->GetTopSites();
   if (!top_sites)
     return;
 
   // Compute the thumbnail score.
   ThumbnailScore score;
   score.at_top =
       (web_contents->GetRenderViewHost()->GetLastScrollOffset().y() == 0);
-  score.boring_score = ThumbnailGenerator::CalculateBoringScore(&thumbnail);
+  score.boring_score = ThumbnailGenerator::CalculateBoringScore(thumbnail);
   score.good_clipping =
       (clip_result == ThumbnailGenerator::kTallerThanWide ||
        clip_result == ThumbnailGenerator::kNotClipped);
   score.load_completed = (!load_interrupted_ && !web_contents->IsLoading());
 
   gfx::Image image(new SkBitmap(thumbnail));
   const GURL& url = web_contents->GetURL();
   top_sites->SetPageThumbnail(url, &image, score);
   VLOG(1) << "Thumbnail taken for " << url << ": " << score.ToString();
 }
@@ skipping 29 matching lines @@
 
 void ThumbnailGenerator::DidStartLoading() {
   load_interrupted_ = false;
 }
 
 void ThumbnailGenerator::StopNavigation() {
   // This function gets called when the page loading is interrupted by the
   // stop button.
   load_interrupted_ = true;
 }