PlzNavigate: fix crash in unit_tests

content/browser/loader/navigation_url_loader_impl_core.cc

Index: content/browser/loader/navigation_url_loader_impl_core.cc
diff --git a/content/browser/loader/navigation_url_loader_impl_core.cc b/content/browser/loader/navigation_url_loader_impl_core.cc
index f7c1dde688b6b9bfd246b8c1887c8c52a392cf4c..05d4b654efd8f0b9d601f2f2bff8f8ecd2ec39bc 100644
--- a/content/browser/loader/navigation_url_loader_impl_core.cc
+++ b/content/browser/loader/navigation_url_loader_impl_core.cc
@@ -47,8 +47,11 @@ void NavigationURLLoaderImplCore::Start(
       base::Bind(&NavigationURLLoaderImpl::NotifyRequestStarted, loader_,
                  base::TimeTicks::Now()));
 
-  ResourceDispatcherHostImpl::Get()->BeginNavigationRequest(
-      resource_context, *request_info, this, service_worker_handle_core);
+  // The ResourceDispatcherHostImpl can be null in unit tests.
+  if (ResourceDispatcherHostImpl::Get()) {

[nasko, 2015/12/03 15:10:27]

Interesting. If we hit this in real code (for some reason), it means the browser
won't be able to navigate, right? I wonder if there is some way to detect
running in test environment.

[clamy, 2015/12/03 16:15:02]

Mm not sure. It's not a change from the current situation though: if you don't
have a ResourceDispatcherHostImpl you can't handle the ResourceRequest from the
renderer.

+    ResourceDispatcherHostImpl::Get()->BeginNavigationRequest(
+        resource_context, *request_info, this, service_worker_handle_core);
+  }
 }
 
 void NavigationURLLoaderImplCore::FollowRedirect() {