PlzNavigate: Enforce 'form-action' CSP on the browser-side.

content/public/browser/navigation_handle.cc

Index: content/public/browser/navigation_handle.cc
diff --git a/content/public/browser/navigation_handle.cc b/content/public/browser/navigation_handle.cc
index 73f59738cd5b84ee525f9a543af0c24ac5d2ed2e..8f8d99d03f79a0b9576470eda021c16e9dbaa365 100644
--- a/content/public/browser/navigation_handle.cc
+++ b/content/public/browser/navigation_handle.cc
@@ -35,8 +35,9 @@ NavigationHandle::CreateNavigationHandleForTesting(
           url, std::vector<GURL>(), rfhi->frame_tree_node(),
           true,  // is_renderer_initiated
           is_same_page, base::TimeTicks::Now(), 0,
-          false,                   // started_from_context_menu
-          CSPDisposition::CHECK);  // should_check_main_world_csp
+          false,                  // started_from_context_menu
+          CSPDisposition::CHECK,  // should_check_main_world_csp
+          false);                 // is_form_submission
   handle_impl->set_render_frame_host(rfhi);
   if (error != net::OK)
     handle_impl->set_net_error_code(error);