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

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 316663e8d0bd645545ca31e9d7e6e8a6e6b62d6d..8123cc6a01e4dd4939f778602da4763ed689dea5 100644
--- a/content/renderer/render_frame_impl.cc
+++ b/content/renderer/render_frame_impl.cc
@@ -6336,6 +6336,11 @@ void RenderFrameImpl::BeginNavigation(const NavigationPolicyInfo& info) {
                     net::LOAD_ONLY_FROM_CACHE | net::LOAD_DISABLE_CACHE);
     load_flags |= net::LOAD_BYPASS_CACHE;
   }
+
+  bool is_form_submission =
+      info.navigationType == blink::WebNavigationTypeFormSubmitted ||
+      info.navigationType == blink::WebNavigationTypeFormResubmitted;
+
   BeginNavigationParams begin_navigation_params(
       GetWebURLRequestHeaders(info.urlRequest), load_flags,
       info.urlRequest.hasUserGesture(),
@@ -6343,7 +6348,7 @@ void RenderFrameImpl::BeginNavigation(const NavigationPolicyInfo& info) {
           blink::WebURLRequest::ServiceWorkerMode::All,
       GetRequestContextTypeForWebURLRequest(info.urlRequest),
       GetMixedContentContextTypeForWebURLRequest(info.urlRequest),
-      initiator_origin);
+      is_form_submission, initiator_origin);
 
   if (!info.form.isNull()) {
     WebSearchableFormData web_searchable_form_data(info.form);