Do not require ContentSubresourceFilterDriverFactory

components/safe_browsing/base_resource_throttle.cc

 // Copyright (c) 2017 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 "components/safe_browsing/base_resource_throttle.h"
 
 #include <iterator>
 #include <utility>
 
 #include "base/debug/alias.h"
@@ skipping 310 matching lines @@
     scoped_refptr<BaseUIManager> ui_manager,
     const security_interstitials::UnsafeResource& resource) {
   content::WebContents* web_contents = resource.web_contents_getter.Run();
   if (web_contents) {
     // Once activated, the subresource filter will filter subresources, but is
     // triggered when the main frame document matches Safe Browsing blacklists.
     if (!resource.is_subresource) {
       using subresource_filter::ContentSubresourceFilterDriverFactory;
       ContentSubresourceFilterDriverFactory* driver_factory =
           ContentSubresourceFilterDriverFactory::FromWebContents(web_contents);
-      DCHECK(driver_factory);
-
-      // For a redirect chain of A -> B -> C, the subresource filter expects C
-      // as the resource URL and [A, B] as redirect URLs.
-      std::vector<GURL> redirect_parent_urls;
-      if (!resource.redirect_urls.empty()) {
-        redirect_parent_urls.push_back(resource.original_url);
-        redirect_parent_urls.insert(redirect_parent_urls.end(),
-                                    resource.redirect_urls.begin(),
-                                    std::prev(resource.redirect_urls.end()));
+      // Content embedders (such as Android Webview) does not have a
+      // driver_factory.
+      if (driver_factory) {
+        // For a redirect chain of A -> B -> C, the subresource filter expects C
+        // as the resource URL and [A, B] as redirect URLs.
+        std::vector<GURL> redirect_parent_urls;
+        if (!resource.redirect_urls.empty()) {
+          redirect_parent_urls.push_back(resource.original_url);
+          redirect_parent_urls.insert(redirect_parent_urls.end(),
+                                      resource.redirect_urls.begin(),
+                                      std::prev(resource.redirect_urls.end()));
+        }
+        driver_factory->OnMainResourceMatchedSafeBrowsingBlacklist(
+            resource.url, redirect_parent_urls, resource.threat_type,
+            resource.threat_metadata.threat_pattern_type);
       }
-
-      driver_factory->OnMainResourceMatchedSafeBrowsingBlacklist(
-          resource.url, redirect_parent_urls, resource.threat_type,
-          resource.threat_metadata.threat_pattern_type);
     }
 
     ui_manager->DisplayBlockingPage(resource);
     return;
   }
 
   // Tab is gone or it's being prerendered.
   content::BrowserThread::PostTask(
       content::BrowserThread::IO, FROM_HERE,
       base::Bind(&BaseResourceThrottle::Cancel, throttle));
@@ skipping 81 matching lines @@
     }
   }
 
   if (resume) {
     defer_state_ = DEFERRED_NONE;
     Resume();
   }
 }
 
 }  // namespace safe_browsing