Small modifications to safebrowsing code to make it simpler to add the extension

chrome/browser/safe_browsing/download_protection_service.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/safe_browsing/download_protection_service.h"
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
 #include "base/format_macros.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 280 matching lines @@
 class DownloadUrlSBClient : public DownloadSBClient {
  public:
   DownloadUrlSBClient(
       const DownloadProtectionService::DownloadInfo& info,
       const DownloadProtectionService::CheckDownloadCallback& callback,
       const scoped_refptr<SafeBrowsingUIManager>& ui_manager,
       const scoped_refptr<SafeBrowsingDatabaseManager>& database_manager)
       : DownloadSBClient(info, callback, ui_manager,
                          DOWNLOAD_URL_CHECKS_TOTAL,
                          DOWNLOAD_URL_CHECKS_MALWARE),
-        database_manager_(database_manager) { }
+        database_manager_(database_manager) {
+    CHECK(database_manager_);

[Scott Hess - ex-Googler, 2013/01/11 23:44:05]

Are you certain?  The code in DownloadProtectionService clearly expects that
NULL database_manager_ is a possibility.  It would be NULL if FULL_SAFE_BROWSING
were not defined.  AFAICT, that applies to iOS and Android, but I don't know
whether in those cases the code would never arrive here, or if the short-circuit
in StartCheck() is expected to take care of it.

[not at google - send to devlin, 2013/01/14 23:00:55]

Yeah, don't know why I made this change.

+  }
 
   virtual void StartCheck() OVERRIDE {
     DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-    if (!database_manager_ || database_manager_->CheckDownloadUrl(
-            info_.download_url_chain, this)) {
+    if (database_manager_->CheckDownloadUrl(info_.download_url_chain, this)) {
       CheckDone(SB_THREAT_TYPE_SAFE);
     } else {
       AddRef();  // SafeBrowsingService takes a pointer not a scoped_refptr.
     }
   }
 
   virtual bool IsDangerous(SBThreatType threat_type) const OVERRIDE {
     return threat_type == SB_THREAT_TYPE_BINARY_MALWARE_URL;
   }
 
@@ skipping 666 matching lines @@
   std::string url = kDownloadRequestUrl;
   std::string api_key = google_apis::GetAPIKey();
   if (!api_key.empty()) {
     base::StringAppendF(&url, "?key=%s",
                         net::EscapeQueryParamValue(api_key, true).c_str());
   }
   return url;
 }
 
 }  // namespace safe_browsing