Added chrome-side support for link rel=preconnect

components/network_hints/renderer/renderer_preconnect.cc

Index: components/network_hints/renderer/renderer_preconnect.cc
diff --git a/components/network_hints/renderer/renderer_preconnect.cc b/components/network_hints/renderer/renderer_preconnect.cc
new file mode 100644
index 0000000000000000000000000000000000000000..9f86420594e8c2d894a7a2f58e30ae005ce60f86
--- /dev/null
+++ b/components/network_hints/renderer/renderer_preconnect.cc
@@ -0,0 +1,62 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.

[Deprecated (see juliatuttle), 2015/02/10 17:48:42]

2015?

[Pat Meenan, 2015/02/10 18:44:49]

Done.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// See header file for description of RendererPreconnect class
+
+#include "components/network_hints/renderer/renderer_preconnect.h"
+
+#include <ctype.h>

[mmenke, 2015/02/10 18:10:14]

What is this needed for?

[Pat Meenan, 2015/02/10 18:44:49]

Removed. Leftover from copying the DNS code to use as a basis.

+
+#include "base/bind.h"
+#include "base/logging.h"
+#include "base/message_loop/message_loop.h"
+#include "components/network_hints/common/network_hints_common.h"
+#include "components/network_hints/common/network_hints_messages.h"
+#include "content/public/renderer/render_thread.h"
+
+using content::RenderThread;
+
+namespace network_hints {
+
+RendererPreconnect::RendererPreconnect()
+    : weak_factory_(this) {
+}
+
+RendererPreconnect::~RendererPreconnect() {
+}
+
+// Push URLs into the map quickly!
+void RendererPreconnect::Preconnect(const GURL &url) {
+  if (!url.is_valid() || !url.has_host() || !url.has_scheme())

[mmenke, 2015/02/10 18:10:14]

GURL can't have relative URLs, I believe.  So the first should imply the next
two.

[Pat Meenan, 2015/02/10 18:44:49]

Done.

+    return;
+
+  // If this is the first entry in the map then a task needs to be scheduled.
+  bool needs_task = url_request_count_map_.empty();
+
+  // ints will initialize to 0 automatically so incrementing will initialize
+  // new URLs to 1 or increment existing URLs (exactly the desired behavior).
+  url_request_count_map_[url]++;
+
+  if (needs_task) {
+    weak_factory_.InvalidateWeakPtrs();
+    RenderThread::Get()->GetTaskRunner()->PostDelayedTask(
+        FROM_HERE, base::Bind(&RendererPreconnect::SubmitPreconnect,

[mmenke, 2015/02/10 18:10:14]

include base/location.h for FROM_HERE

[Pat Meenan, 2015/02/10 18:44:49]

Done. The DNS prefetch code was doing the same thing so I added base/location.h
there as well.

+                              weak_factory_.GetWeakPtr()),
+        base::TimeDelta::FromMilliseconds(10));
+  }
+}
+
+// Extract data from the Map, and then send it off the the Browser process
+// to be preconnected.
+void RendererPreconnect::SubmitPreconnect() {
+  DCHECK(!url_request_count_map_.empty());
+  for (UrlRequestCountMap::iterator it = url_request_count_map_.begin();
+       it != url_request_count_map_.end(); ++it) {

[mmenke, 2015/02/10 18:10:14]

Use a C++x11 range loop?  const auto&...  (If I weren't suggesting you change
the loop, I'd suggest this use const_iterator)

[Pat Meenan, 2015/02/10 18:44:49]

Done.

+    RenderThread::Get()->Send(
+        new NetworkHintsMsg_Preconnect(it->first, it->second));
+  }
+  url_request_count_map_.clear();
+}
+
+}  // namespcae network_hints

[mmenke, 2015/02/10 18:10:14]

typo:  namespace

[Pat Meenan, 2015/02/10 18:44:49]

Done. Typo was copied from the DNS prefetch code so I fixed it over there as
well.