PlzNavigate: store POST data in the FrameNavigationEntry

content/browser/frame_host/navigation_request.cc

Index: content/browser/frame_host/navigation_request.cc
diff --git a/content/browser/frame_host/navigation_request.cc b/content/browser/frame_host/navigation_request.cc
index 159c6a0357375327207fa92f9940e7bcda8aa0c5..f79963e477ba40bbce36b8c2bab061a6a70879ff 100644
--- a/content/browser/frame_host/navigation_request.cc
+++ b/content/browser/frame_host/navigation_request.cc
@@ -80,20 +80,23 @@ std::unique_ptr<NavigationRequest> NavigationRequest::CreateBrowserInitiated(
   headers.SetHeaderIfMissing(net::HttpRequestHeaders::kUserAgent,
                              GetContentClient()->GetUserAgent());
 
-  // Fill POST data from the browser in the request body.
+  // Fill POST data in the request body.
   scoped_refptr<ResourceRequestBody> request_body;
-  if (entry.GetHasPostData()) {
-    request_body = new ResourceRequestBody();
-    request_body->AppendBytes(
-        reinterpret_cast<const char *>(
-            entry.GetBrowserInitiatedPostData()->front()),
-        entry.GetBrowserInitiatedPostData()->size());
+  if (frame_entry.method() == "POST") {
+    request_body = frame_entry.GetPostData();
+    if (!request_body && entry.GetBrowserInitiatedPostData()) {
+      request_body = new ResourceRequestBody();
+      request_body->AppendBytes(
+          reinterpret_cast<const char*>(
+              entry.GetBrowserInitiatedPostData()->front()),
+          entry.GetBrowserInitiatedPostData()->size());
+    }
   }
 
   std::unique_ptr<NavigationRequest> navigation_request(new NavigationRequest(
       frame_tree_node, entry.ConstructCommonNavigationParams(
-                           dest_url, dest_referrer, navigation_type, lofi_state,
-                           navigation_start),
+                           frame_entry, dest_url, dest_referrer,
+                           navigation_type, lofi_state, navigation_start),
       BeginNavigationParams(headers.ToString(),
                             LoadFlagFromNavigationType(navigation_type),
                             false,  // has_user_gestures
@@ -196,6 +199,9 @@ NavigationRequest::NavigationRequest(
       common_params, begin_params, first_party_for_cookies,
       frame_tree_node->current_origin(), frame_tree_node->IsMainFrame(),
       parent_is_main_frame, frame_tree_node->frame_tree_node_id(), body));
+
+  if (body)
+    post_data_ = body->MakeCopy();

[Łukasz Anforowicz, 2016/05/12 02:53:59]

Can you help me understand why we need to make a deep copy here (rather than
just take another ref-count)?  I thought that ResourceRequestBody would never be
changed after initial construction - is this not the case / is there a need to
mutate ResourceRequestBody in some cases?

[clamy, 2016/05/12 08:53:13]

I wasn't sure about this so I made a copy to stay safe. If someone from the net
stack team explained that it would not be changed, then it's probably safe not
to make a copy.

[Łukasz Anforowicz, 2016/05/12 19:44:12]

I think it should be safe not to make a copy - I've tried to look at the callers
of ResourceRequestBody's non-const methods (AppendBytes, AppendFileRange,
AppendBlob, AppendFileSystemFileRange, elements_mutable, swap_elements,
set_identifier) and they appear to only come from code that constructs a fresh
ResourceRequestBody (or from test code).

Interestingly Cr Code Search was not able to find users of elements_mutable. 
Seems like a job for Scythe :-)

So - I would vote from removing the deep copy, but you are right, that it might
be a good idea to double-check this with a //net person.

[Charlie Reis, 2016/05/16 21:16:41]

+1 to removing the deep copy if we can.

[clamy, 2016/05/19 13:11:57]

Done.

 }
 
 NavigationRequest::~NavigationRequest() {
@@ -256,6 +262,10 @@ void NavigationRequest::TransferNavigationHandleOwnership(
 void NavigationRequest::OnRequestRedirected(
     const net::RedirectInfo& redirect_info,
     const scoped_refptr<ResourceResponse>& response) {
+  // If the navigation is no longer a POST, the POST data should be reset.
+  if (common_params_.method == "POST" && redirect_info.new_method != "POST")

[Łukasz Anforowicz, 2016/05/12 02:53:59]

Shouldn't the second part of the condition be sufficient?  (i.e. we don't really
need to consult |common_params_.method|, right?)

[clamy, 2016/05/12 08:53:13]

No but I thought it made a bit clearer the case in which we actually reset the
request. Can remove the second part if needed.

[Łukasz Anforowicz, 2016/05/12 19:44:12]

Acknowledged.  I don't strongly feel one way or another.

[Charlie Reis, 2016/05/16 21:16:41]

I think we should remove the first part (common_params_.method == "POST").  It's
not likely that post_data_ will exist when common_params_.method != "POST", but
if it did, it would be bad to preserve it after a redirect to a GET.

+    post_data_ = nullptr;
+
   common_params_.url = redirect_info.new_url;
   common_params_.method = redirect_info.new_method;
   common_params_.referrer.url = GURL(redirect_info.new_referrer);
@@ -421,7 +431,7 @@ void NavigationRequest::CommitNavigation() {
   TransferNavigationHandleOwnership(render_frame_host);
   render_frame_host->CommitNavigation(response_.get(), std::move(body_),
                                       common_params_, request_params_,
-                                      is_view_source_);
+                                      is_view_source_, post_data_);
 
   // When navigating to a Javascript url, the NavigationRequest is not stored
   // in the FrameTreeNode. Therefore do not reset it, as this could cancel an