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

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 75f670885fe1fb5088b338c4defc57a134682138..3e0d45f6ccec39daff57f258fc7884884fcb2587 100644
--- a/content/browser/frame_host/render_frame_host_impl.cc
+++ b/content/browser/frame_host/render_frame_host_impl.cc
@@ -3467,7 +3467,8 @@ RenderFrameHostImpl::TakeNavigationHandleForCommit(
         params.was_within_same_page, base::TimeTicks::Now(),
         pending_nav_entry_id,
         false,   // started_from_context_menu
-        false);  // should_bypass_main_world_csp
+        false,   // should_bypass_main_world_csp
+        false);  // is_form_submission
   }
 
   // Determine if the current NavigationHandle can be used.
@@ -3521,7 +3522,8 @@ RenderFrameHostImpl::TakeNavigationHandleForCommit(
       params.was_within_same_page, base::TimeTicks::Now(),
       entry_id_for_data_nav,
       false,   // started_from_context_menu
-      false);  // should_bypass_main_world_csp
+      false,   // should_bypass_main_world_csp
+      false);  // is_form_submission
 }
 
 #if defined(OS_ANDROID)