Collect some histograms about signed binary downloads.

chrome/browser/safe_browsing/client_side_detection_host_unittest.cc

 // Copyright (c) 2011 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 "base/file_path.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/task.h"
 #include "chrome/browser/safe_browsing/browser_feature_extractor.h"
 #include "chrome/browser/safe_browsing/client_side_detection_host.h"
@@ skipping 152 matching lines @@
     csd_host_.reset(safe_browsing::ClientSideDetectionHost::Create(
         contents_wrapper()->tab_contents()));
     csd_host_->set_client_side_detection_service(csd_service_.get());
     csd_host_->set_safe_browsing_service(sb_service_.get());
     // We need to create this here since we don't call
     // DidNavigateMainFramePostCommit in this test.
     csd_host_->browse_info_.reset(new BrowseInfo);
   }
 
   virtual void TearDown() {
-    // Delete the host object on the UI thread.
+    // Delete the host object on the UI thread and release the
+    // SafeBrowsingService.
     BrowserThread::PostTask(
         BrowserThread::UI,
         FROM_HERE,
         new DeleteTask<ClientSideDetectionHost>(csd_host_.release()));
+    sb_service_ = NULL;
     message_loop_.RunAllPending();
     TabContentsWrapperTestHarness::TearDown();
     io_thread_.reset();
     ui_thread_.reset();
   }
 
   void OnPhishingDetectionDone(const std::string& verdict_str) {
     csd_host_->OnPhishingDetectionDone(verdict_str);
   }
 
@@ skipping 549 matching lines @@
   EXPECT_TRUE(Mock::VerifyAndClear(sb_service_.get()));
   EXPECT_EQ(url, resource.url);
   EXPECT_EQ(url, resource.original_url);
   delete resource.client;
   msg = process()->sink().GetFirstMessageMatching(
       SafeBrowsingMsg_StartPhishingDetection::ID);
   ASSERT_FALSE(msg);
 }
 
 }  // namespace safe_browsing