Declarative resource hints go through mojo IPC to //content

third_party/WebKit/Source/platform/network/NetworkHints.cpp

 /*
  * Copyright (C) 2008 Collin Jackson  <collinj@webkit.org>
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "platform/network/NetworkHints.h"
 
 #include "public/platform/Platform.h"
+#include "public/platform/ServiceRegistry.h"
 #include "public/platform/WebPrescientNetworking.h"
 
 namespace blink {
 
-void prefetchDNS(const String& hostname)
+void speculativePrefetchDNS(const String& hostname)
 {
     if (WebPrescientNetworking* prescientNetworking = Platform::current()->prescientNetworking())
         prescientNetworking->prefetchDNS(hostname);
 }
 
 void preconnect(const KURL& url, const CrossOriginAttributeValue crossOrigin)
 {
-    if (WebPrescientNetworking* prescientNetworking = Platform::current()->prescientNetworking()) {
-        bool allowCredentials = (crossOrigin != CrossOriginAttributeAnonymous);
-        prescientNetworking->preconnect(url, allowCredentials);
-    }
+    ResourceHintsDispatcher::instance().preconnect(url, crossOrigin, 1);
+}
+
+void prefetchDNS(const KURL& url)
+{
+    ResourceHintsDispatcher::instance().preresolve(url);
+}
+
+// static
+ResourceHintsDispatcher& ResourceHintsDispatcher::instance()
+{
+    DEFINE_STATIC_LOCAL(ResourceHintsDispatcher, dispatcher, ());

[kinuko, 2016/06/09 07:09:19]

For platform-level mojo calls I'm still not fully sure if we should just keep
adding these as static (I imagine we'll have more)... I think we could possibly
think about gathering these in a single place, e.g. within Platform.

[Charlie Harrison, 2016/06/10 14:20:00]

Good idea. This will make testing simpler too (I think we can use MockPlatform
instead of mocking NetworkHintsInterface).

+    return dispatcher;
+}
+
+void ResourceHintsDispatcher::preconnect(const KURL& url, CrossOriginAttributeValue crossOrigin, int numConnections)
+{
+    bool credentialsFlag = (crossOrigin != CrossOriginAttributeAnonymous);
+    m_host->DispatchPreconnect(url, credentialsFlag, numConnections);
+}
+
+void ResourceHintsDispatcher::preresolve(const KURL& url)
+{
+    m_host->DispatchPreresolve(url);
+}
+
+ResourceHintsDispatcher::ResourceHintsDispatcher()
+{
+    DCHECK(!m_host.is_bound());

[yzshen1, 2016/06/08 17:40:53]

nit: this DCHECK is not very useful because default constructed InterfacePtr is
always not bound.

[Charlie Harrison, 2016/06/10 14:20:00]

Done.

+    Platform::current()->serviceRegistry()->connectToRemoteService(mojo::GetProxy(&m_host));
 }
 
 } // namespace blink