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

third_party/WebKit/Source/core/loader/FrameLoader.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights
  * reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  * Copyright (C) 2008 Alp Toker <alp@atoker.com>
  * Copyright (C) Research In Motion Limited 2009. All rights reserved.
  * Copyright (C) 2011 Kris Jordan <krisjordan@gmail.com>
  * Copyright (C) 2011 Google Inc. All rights reserved.
@@ skipping 1675 matching lines @@
         m_frame->document()->enforceSandboxFlags(SandboxOrigin);
         m_frame->owner()->dispatchLoad();
         return NavigationPolicyIgnore;
       }
     }
   }
 
   bool isFormSubmission = type == NavigationTypeFormSubmitted ||
                           type == NavigationTypeFormResubmitted;
   if (isFormSubmission &&
+      // 'form-action' check in the frame that is navigating is disabled on the
+      // renderer side when PlzNavigate is enabled, but is enforced on the
+      // browser side instead.
+      // N.B. check in the frame that initiates the navigation stills occurs in
+      // blink and is not enforced on the browser-side.
+      // TODO(arthursonzogni) The 'form-action' check should be fully disabled
+      // in blink when browser side navigation is enabled, except when the form
+      // submission doesn't trigger a navigation(i.e. javascript urls). Please
+      // see https://crbug.com/701749
+      !browserSideNavigationEnabled &&
       !m_frame->document()->contentSecurityPolicy()->allowFormAction(
           request.url(), request.redirectStatus())) {
     return NavigationPolicyIgnore;
   }
 
   bool replacesCurrentHistoryItem =
       frameLoadType == FrameLoadTypeReplaceCurrentItem;
   policy = client()->decidePolicyForNavigation(
       request, loader, type, policy, replacesCurrentHistoryItem,
       isClientRedirect, form, shouldCheckMainWorldContentSecurityPolicy);
@@ skipping 322 matching lines @@
       frameLoadRequest.clientRedirect());
 
   loader->setLoadType(loadType);
   loader->setNavigationType(navigationType);
   loader->setReplacesCurrentHistoryItem(loadType ==
                                         FrameLoadTypeReplaceCurrentItem);
   return loader;
 }
 
 }  // namespace blink