Add WebPrescientNetworking to trigger preconnect from Blink.

Source/Platform/chromium/public/WebPrescientNetworking.h

 /*
  * 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 10 matching lines @@
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER 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.
  */
 
-#ifndef WebGraphicsContext3DProvider_h
-#define WebGraphicsContext3DProvider_h
+#ifndef WebPrescientNetworking_h
+#define WebPrescientNetworking_h
 
 #include "WebCommon.h"
 
-class GrContext;
+namespace WebKit {
 
-namespace WebKit {
-class WebGraphicsContext3D;
+class WebURL;
 
-class WebGraphicsContext3DProvider {
+// FIXME: Passing preconnect motivation to the platform is layering vioration.
+// However, this is done temporarily to perform a Finch field trial to enable
+// preconnect in different triggers one at a time. This enum can be safely
+// removed after the field trial is done.
+enum WebPreconnectMotivation {
+    WebPreconnectMotivationLinkMouseDown,
+    WebPreconnectMotivationLinkMouseOver,
+    WebPreconnectMotivationLinkTapUnconfirmed,
+    WebPreconnectMotivationLinkTapDown,
+};
+
+class WebPrescientNetworking {
 public:
-    virtual ~WebGraphicsContext3DProvider() { }
+    virtual ~WebPrescientNetworking() { }
 
-    virtual WebGraphicsContext3D* context3d() = 0;
-    virtual GrContext* grContext() = 0;
+    // When a page navigation is speculated, preconnect is triggered to hide
+    // session initialization latency to the server providing the page resource.
+    virtual void preconnect(const WebURL&, WebPreconnectMotivation) { }
 };
 
 } // namespace WebKit
 
-#endif
+#endif // WebPrescientNetworking_h