Implement transfer navigation with mojo

content/browser/loader/mojo_async_resource_handler.cc

Index: content/browser/loader/mojo_async_resource_handler.cc
diff --git a/content/browser/loader/mojo_async_resource_handler.cc b/content/browser/loader/mojo_async_resource_handler.cc
index 1288fe45136fb67142fa4ca4383a058c83eb14e9..958656e520a03207d891f0cdac6d0a2cd22d1d69 100644
--- a/content/browser/loader/mojo_async_resource_handler.cc
+++ b/content/browser/loader/mojo_async_resource_handler.cc
@@ -111,7 +111,8 @@ MojoAsyncResourceHandler::MojoAsyncResourceHandler(
     : ResourceHandler(request),
       rdh_(rdh),
       binding_(this, std::move(mojo_request)),
-      url_loader_client_(std::move(url_loader_client)) {
+      url_loader_client_(std::move(url_loader_client)),
+      weak_factory_(this) {
   DCHECK(url_loader_client_);
   InitializeResourceBufferConstants();
   // This unretained pointer is safe, because |binding_| is owned by |this| and
@@ -125,6 +126,12 @@ MojoAsyncResourceHandler::~MojoAsyncResourceHandler() {
     rdh_->FinishedWithResourcesForRequest(request());
 }
 
+MojoAsyncResourceHandler::TransferCallback
+MojoAsyncResourceHandler::GetTransferCallback() {
+  return base::Bind(&MojoAsyncResourceHandler::OnTransfer,
+                    weak_factory_.GetWeakPtr());
+}
+
 bool MojoAsyncResourceHandler::OnRequestRedirected(
     const net::RedirectInfo& redirect_info,
     ResourceResponse* response,
@@ -438,4 +445,19 @@ void MojoAsyncResourceHandler::ReportBadMessage(const std::string& error) {
   mojo::ReportBadMessage(error);
 }
 
+void MojoAsyncResourceHandler::OnTransfer(
+    mojom::URLLoaderAssociatedRequest mojo_request,
+    mojom::URLLoaderClientAssociatedPtr url_loader_client) {
+  if (!url_loader_client) {
+    // Resumes the request without transferring it to a new process.
+    return;
+  }
+
+  binding_.Unbind();
+  binding_.Bind(std::move(mojo_request));
+  binding_.set_connection_error_handler(
+      base::Bind(&MojoAsyncResourceHandler::Cancel, base::Unretained(this)));
+  url_loader_client_ = std::move(url_loader_client);
+}
+
 }  // namespace content