exhibit 1: explicit null checks

chrome/browser/favicon/favicon_tab_helper.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/favicon_tab_helper.h"
 
 #include "chrome/browser/favicon/favicon_handler.h"
 #include "chrome/browser/favicon/favicon_util.h"
 #include "chrome/browser/favicon/select_favicon_frames.h"
 #include "chrome/browser/history/history.h"
@@ skipping 98 matching lines @@
   if (!service)
     return;
   const FaviconStatus& favicon(entry->GetFavicon());
   if (!favicon.valid || favicon.url.is_empty() ||
       favicon.image.IsEmpty()) {
     return;
   }
   std::vector<unsigned char> image_data;
   // TODO: Save all representations.
   gfx::PNGCodec::EncodeBGRASkBitmap(
-      favicon.image.AsBitmap(), false, &image_data);
+      *favicon.image.ToSkBitmap(), false, &image_data);
   service->SetFavicon(
       entry->GetURL(), favicon.url, image_data, history::FAVICON);
 }
 
 int FaviconTabHelper::DownloadImage(const GURL& image_url,
                                  int image_size,
                                  history::IconType icon_type,
                                  const ImageDownloadCallback& callback) {
   if (icon_type == history::FAVICON)
     return favicon_handler_->DownloadImage(image_url, image_size, icon_type,
@@ skipping 72 matching lines @@
   scale_factors = ui::GetSupportedScaleFactors();
 #else
   scale_factors.push_back(ui::SCALE_FACTOR_100P);  // TODO: Aura?
 #endif
   gfx::Image favicon(
       SelectFaviconFrames(bitmaps, scale_factors, requested_size));
   favicon_handler_->OnDidDownloadFavicon(id, image_url, errored, favicon);
   if (touch_icon_handler_.get())
     touch_icon_handler_->OnDidDownloadFavicon(id, image_url, errored, favicon);
 }