NavigationMojoResponse: Remove the old code path [3/4]

Remove the IsNavigationMojoResponseEnabled() function and every mention
of "NavigationMojoResponse" in the code.

Other CLs:
  1) https://chromium-review.googlesource.com/c/chromium/src/+/1015005
  2) https://chromium-review.googlesource.com/c/chromium/src/+/1021631
* 3) https://chromium-review.googlesource.com/c/chromium/src/+/1022790
  4) https://chromium-review.googlesource.com/c/chromium/src/+/1024038

Bug: 705744
Change-Id: Ia755a96901d08819d0b10417965e292821415c44
Reviewed-on: https://chromium-review.googlesource.com/1022790
Commit-Queue: Arthur Sonzogni <[email protected]>
Reviewed-by: Varun Khaneja <[email protected]>
Reviewed-by: John Abd-El-Malek <[email protected]>
Reviewed-by: Kinuko Yasuda <[email protected]>
Cr-Commit-Position: refs/heads/master@{#553243}
diff --git a/content/renderer/loader/url_loader_client_impl.h b/content/renderer/loader/url_loader_client_impl.h
index 96712b0..66c1a45 100644
--- a/content/renderer/loader/url_loader_client_impl.h
+++ b/content/renderer/loader/url_loader_client_impl.h
@@ -60,10 +60,9 @@
 
   // Binds this instance to the given URLLoaderClient endpoints so that it can
   // start getting the mojo calls from the given loader. This is used only for
-  // the main resource loading when NavigationMojoResponse and/or NetworkService
-  // is enabled. Otherwise (in regular subresource loading cases) |this| is not
-  // bound to a client request, but used via ThrottlingURLLoader to get client
-  // upcalls from the loader.
+  // the main resource loading. Otherwise (in regular subresource loading cases)
+  // |this| is not bound to a client request, but used via ThrottlingURLLoader
+  // to get client upcalls from the loader.
   void Bind(
       network::mojom::URLLoaderClientEndpointsPtr url_loader_client_endpoints);
 
@@ -112,7 +111,6 @@
   ResourceDispatcher* const resource_dispatcher_;
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 
-  // Used in NavigationMojoResponse and NetworkService.
   network::mojom::URLLoaderPtr url_loader_;
   mojo::Binding<network::mojom::URLLoaderClient> url_loader_client_binding_;