Readded code to get top document GURL in NavigationRequest.

We patch NavigationRequest::OnStartChecksComplete to call
MaybeHideReferrer. One of the params to MaybeHideReferrer is top
document GURL which was available in OnStartCheckComplete. The Chromium
change below removed it. Added a chromium_src override that includes
GetTopDocumentGURL function that containes the deleted functionality.

Chromium change:

https://chromium.googlesource.com/chromium/src/+/435bcb58bb2c75be8276f1dde69fc6c9891c45ba

commit 435bcb58bb2c75be8276f1dde69fc6c9891c45ba
Author: Lukasz Anforowicz <lukasza@chromium.org>
Date:   Fri Jul 12 20:50:06 2019 +0000

    Store |initiator_origin| in FrameNavigationEntry.

    Changes in this CL
    ==================

    This CL:

    1. Updates FrameNavigationEntry::UpdateEntry and
       FrameNavigationEntry's constructor so that they both take
       |const base::Optional<url::Origin>& initiator_origin| which
       gets stored in a new FrameNavigationEntry::initiator_origin_ field.

    2. Updates callers of FNE::UpdateEntry and FNE's constructor to
       provide/propagate the initiator as needed.  This includes
       adding an |initiator_origin| parameter to
       - NavigationEntryImpl's constructor
       - NavigationEntryImpl::AddOrUpdateFrameEntry
       - NavigationController::CreateNavigationEntry
       (the list above is not necessarily exhaustive/complete)

    3. Uses the new |FrameNavigationEntry::initiator_origin()| from
       NavigationEntryImpl::ConstructCommonNavigationParams (which
       used to always provide |base::nullopt| initiator for history
       navigations - always treating them as browser-initiated, rather
       than replaying the original initiator).

    The changes above makes sure that the right Sec-Fetch-Site http request header is
    "replayed" during history navigations.  The CL adds browser tests and
    WPT tests to cover the new, desired behavior.

    Follow-up changes
    =================

    This CL does not:

    - Use |FrameNavigationEntry::initiator_origin()| in GetOriginForURLLoaderFactory
      in render_frame_host_impl.cc (this will be done in a follow-up CL at
      https://crrev.com/c/1672176)

    - Handle persisting |FrameNavigationEntry::initiator_origin()| for
      session restore (this is tracked in a separate https://crbug.com/976055).

    Bug: 946503

chromium_src/content/browser/frame_host/navigation_request.cc

@@ -0,0 +1,41 @@
+/* Copyright (c) 2019 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "content/browser/frame_host/frame_tree.h"
+#include "content/browser/frame_host/frame_tree_node.h"
+#include "url/gurl.h"
+
+#if defined(OS_ANDROID)
+#include "content/browser/frame_host/navigator.h"
+#include "content/public/browser/navigation_controller.h"
+#include "content/public/browser/navigation_entry.h"
+#endif
+
+namespace {
+
+GURL GetTopDocumentGURL(const content::FrameTreeNode* frame_tree_node) {
+  GURL gurl;
+#if defined(OS_ANDROID)
+  // On Android, a base URL can be set for the frame. If this the case, it is
+  // the URL to use for cookies.
+  content::NavigationEntry* last_committed_entry =
+      frame_tree_node_->navigator()->GetController()->GetLastCommittedEntry();
+  if (last_committed_entry)
+    gurl = last_committed_entry->GetBaseURLForDataURL();
+#endif
+  if (gurl.is_empty())
+    gurl = frame_tree_node->frame_tree()->root()->current_url();
+  return gurl;
+}
+
+}  // namespace
+
+#define BRAVE_ONSTARTCHECKSCOMPLETE_MAYBEHIDEREFERRER                        \
+  GetContentClient()->browser()->MaybeHideReferrer(                          \
+      browser_context, common_params_.url,                                   \
+      GetTopDocumentGURL(frame_tree_node_), frame_tree_node_->IsMainFrame(), \
+      &common_params_.referrer);
+
+#include "../../../../../content/browser/frame_host/navigation_request.cc"

patches/content-browser-frame_host-navigation_request.cc.patch

@@ -1,21 +1,12 @@
 diff --git a/content/browser/frame_host/navigation_request.cc b/content/browser/frame_host/navigation_request.cc
-index f8d5c526f2f7074130823267d6615a6bd6298112..3be1a1a13b3ded4d54ac7699b56e8e8f904f8afb 100644
+index f8d5c526f2f7074130823267d6615a6bd6298112..848d39fd5dd746644bdc0f80dfa8dd7dda4965d6 100644
 --- a/content/browser/frame_host/navigation_request.cc
 +++ b/content/browser/frame_host/navigation_request.cc
-@@ -1747,9 +1747,16 @@ void NavigationRequest::OnStartChecksComplete(
+@@ -1747,6 +1747,7 @@ void NavigationRequest::OnStartChecksComplete(
    headers.MergeFrom(navigation_handle_->TakeModifiedRequestHeaders());
    begin_params_->headers = headers.ToString();
 
-+  GetContentClient()->browser()->MaybeHideReferrer(browser_context,
-+                                                   common_params_.url,
-+                                                   top_document_url,
-+                                                   frame_tree_node_->IsMainFrame(),
-+                                                   &common_params_.referrer);
-+
++  BRAVE_ONSTARTCHECKSCOMPLETE_MAYBEHIDEREFERRER
    std::vector<std::unique_ptr<NavigationLoaderInterceptor>> interceptor;
    if (bundled_exchanges_factory_)
      interceptor.push_back(bundled_exchanges_factory_->CreateInterceptor());
-+
-   loader_ = NavigationURLLoader::Create(
-       browser_context, browser_context->GetResourceContext(), partition,
-       std::make_unique<NavigationRequestInfo>(