PlzNavigate: Speculatively spawns a renderer process for navigations.

content/test/test_web_contents.cc

Index: content/test/test_web_contents.cc
diff --git a/content/test/test_web_contents.cc b/content/test/test_web_contents.cc
index 6a2e05e2b9cc805bcd8109b20f72f186841f8c35..59d98c4966cdd8fb749ac11baccd547b0b23f4c8 100644
--- a/content/test/test_web_contents.cc
+++ b/content/test/test_web_contents.cc
@@ -154,7 +154,8 @@ void TestWebContents::CommitPendingNavigation() {
   // proper renderer.
   old_rfh->PrepareForCommit(entry->GetURL());
 
-  TestRenderFrameHost* rfh = GetPendingMainFrame();
+  TestRenderFrameHost* rfh = GetFutureMainFrame();
+
   if (!rfh)
     rfh = old_rfh;
 
@@ -227,6 +228,15 @@ void TestWebContents::TestDidFailLoadWithError(
   frame_tree_.root()->current_frame_host()->OnMessageReceived(msg);
 }
 
+TestRenderFrameHost* TestWebContents::GetFutureMainFrame() const {
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableBrowserSideNavigation)) {
+    return static_cast<TestRenderFrameHost*>(
+        GetRenderManager()->speculative_render_frame_host_.get());
+  }
+  return GetPendingMainFrame();
+}
+
 void TestWebContents::CreateNewWindow(
     int render_process_id,
     int route_id,