NavigationThrottleRunner2: void CreateThrottlesForNavigation

Change the CreateThrottlesForNavigation's signature to deprecate
legacy registration approach, returning a vector.

Bug: 412524375
Change-Id: Ia7bc8b6ed7e8407ef3b0b3d2e559a7a1c12b5638
Cq-Include-Trybots: luci.chromium.try:android-cast-arm64-rel
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6493688
Reviewed-by: Nate Fischer <[email protected]>
Reviewed-by: Alex Moshchuk <[email protected]>
Commit-Queue: Takashi Toyoshima <[email protected]>
Reviewed-by: Andrey Kosyakov <[email protected]>
Reviewed-by: Devlin Cronin <[email protected]>
Reviewed-by: Simeon Anfinrud <[email protected]>
Reviewed-by: David Dorwin <[email protected]>
Reviewed-by: Nidhi Jaju <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1456795}
diff --git a/content/browser/renderer_host/navigation_request_unittest.cc b/content/browser/renderer_host/navigation_request_unittest.cc
index 10505c2e..d4a96ab 100644
--- a/content/browser/renderer_host/navigation_request_unittest.cc
+++ b/content/browser/renderer_host/navigation_request_unittest.cc
@@ -592,13 +592,11 @@
 };
 
 class ThrottleTestContentBrowserClient : public ContentBrowserClient {
-  std::vector<std::unique_ptr<NavigationThrottle>> CreateThrottlesForNavigation(
+  void CreateThrottlesForNavigation(
       NavigationThrottleRegistry& registry) override {
-    std::vector<std::unique_ptr<NavigationThrottle>> throttle;
     registry.AddThrottle(
         std::make_unique<GetRenderFrameHostOnFailureNavigationThrottle>(
             &registry.GetNavigationHandle()));
-    return throttle;
   }
 };