PlzNavigate: implement RequestNavigation in the no live renderer case

content/browser/frame_host/render_frame_host_impl.cc

Index: content/browser/frame_host/render_frame_host_impl.cc
diff --git a/content/browser/frame_host/render_frame_host_impl.cc b/content/browser/frame_host/render_frame_host_impl.cc
index 9127f4b8ba0d54e9e2d3b89d814b5672e1ae1e20..20d519fab496290289d8a771e58798c5f9db45ba 100644
--- a/content/browser/frame_host/render_frame_host_impl.cc
+++ b/content/browser/frame_host/render_frame_host_impl.cc
@@ -5,6 +5,7 @@
 #include "content/browser/frame_host/render_frame_host_impl.h"
 
 #include "base/bind.h"
+#include "base/command_line.h"
 #include "base/containers/hash_tables.h"
 #include "base/lazy_instance.h"
 #include "base/metrics/histogram.h"
@@ -46,6 +47,7 @@
 #include "content/public/browser/render_widget_host_view.h"
 #include "content/public/browser/user_metrics.h"
 #include "content/public/common/content_constants.h"
+#include "content/public/common/content_switches.h"
 #include "content/public/common/url_constants.h"
 #include "content/public/common/url_utils.h"
 #include "ui/accessibility/ax_tree.h"
@@ -928,9 +930,9 @@ void RenderFrameHostImpl::OnUpdateEncoding(const std::string& encoding_name) {
 
 void RenderFrameHostImpl::OnBeginNavigation(
     const FrameHostMsg_BeginNavigation_Params& params) {
-#if defined(USE_BROWSER_SIDE_NAVIGATION)
+  CHECK(CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kEnableBrowserSideNavigation));
   frame_tree_node()->render_manager()->OnBeginNavigation(params);
-#endif
 }
 
 void RenderFrameHostImpl::OnAccessibilityEvents(