PlzNavigate: Do not send synchronous navigations from the renderer to the browser.

content/renderer/render_frame_impl.cc

Index: content/renderer/render_frame_impl.cc
diff --git a/content/renderer/render_frame_impl.cc b/content/renderer/render_frame_impl.cc
index 2e7d77a987884907027c9592b092779f2be946ff..c269f7d5348c2f63d3cc3e8e2d24268932998167 100644
--- a/content/renderer/render_frame_impl.cc
+++ b/content/renderer/render_frame_impl.cc
@@ -4329,10 +4329,12 @@ WebNavigationPolicy RenderFrameImpl::DecidePolicyForNavigation(
     return blink::WebNavigationPolicyIgnore;
   }
 
-  // PlzNavigate: send the request to the browser if needed.
+  // PlzNavigate: if the navigation is not synchronous, send it to the browser.
+  // This includes navigations with no request being sent to the network stack.
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kEnableBrowserSideNavigation) &&
-      info.urlRequest.checkForBrowserSideNavigation()) {
+      info.urlRequest.checkForBrowserSideNavigation() &&
+      ShouldMakeNetworkRequestForURL(url)) {
     BeginNavigation(&info.urlRequest);
     return blink::WebNavigationPolicyIgnore;
   }