Make image_decoder a Leaky LazyInstance

chrome/browser/bitmap_fetcher/bitmap_fetcher_service_unittest.cc

 // Copyright 2014 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/bitmap_fetcher/bitmap_fetcher_service.h"
 
 #include "chrome/browser/bitmap_fetcher/bitmap_fetcher.h"
 #include "chrome/test/base/testing_profile.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ skipping 60 matching lines @@
   // Simulate finishing a URL fetch and decode for the given fetcher.
   void CompleteFetch(const GURL& url) {
     const chrome::BitmapFetcher* fetcher = service_->FindFetcherForUrl(url);
     ASSERT_TRUE(NULL != fetcher);
 
     // Create a non-empty bitmap.
     SkBitmap image;
     image.allocN32Pixels(2, 2);
     image.eraseColor(SK_ColorGREEN);
 
-    const_cast<chrome::BitmapFetcher*>(fetcher)->OnImageDecoded(NULL, image);
+    const_cast<chrome::BitmapFetcher*>(fetcher)->OnImageDecoded(image);
   }
 
   void FailFetch(const GURL& url) {
     const chrome::BitmapFetcher* fetcher = service_->FindFetcherForUrl(url);
     ASSERT_TRUE(NULL != fetcher);
-    const_cast<chrome::BitmapFetcher*>(fetcher)
-        ->OnImageDecoded(NULL, SkBitmap());
+    const_cast<chrome::BitmapFetcher*>(fetcher)->OnImageDecoded(SkBitmap());
   }
 
  protected:
   scoped_ptr<BitmapFetcherService> service_;
 
   int imagesChanged_;
   int requestsFinished_;
 
   GURL url1_;
   GURL url2_;
@@ skipping 64 matching lines @@
   service_->RequestImage(url1_, new TestObserver(this));
   service_->RequestImage(url2_, new TestObserver(this));
   EXPECT_EQ(0U, cache_size());
 
   CompleteFetch(url1_);
   EXPECT_EQ(1U, cache_size());
 
   FailFetch(url2_);
   EXPECT_EQ(1U, cache_size());
 }