Add IDL and initial Blink API for Background Sync

public/platform/Platform.h

 /*
  * Copyright (C) 2012 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 42 matching lines @@
 #include "WebStorageQuotaType.h"
 #include "WebString.h"
 #include "WebURLError.h"
 #include "WebVector.h"
 
 class GrContext;
 
 namespace blink {
 
 class WebAudioBus;
+class WebSyncProvider;
 class WebBlobRegistry;
 class WebBluetooth;
 class WebClipboard;
 class WebCompositorSupport;
 class WebConvertableToTraceFormat;
 class WebCookieJar;
 class WebCrypto;
 class WebDatabaseObserver;
 class WebDiscardableMemory;
 class WebPlatformEventListener;
@@ skipping 574 matching lines @@
     // Bluetooth ----------------------------------------------------------
 
     // Returns pointer to client owned WebBluetooth implementation.
     virtual WebBluetooth* bluetooth() { return 0; }
 
 
     // Push API------------------------------------------------------------
 
     virtual WebPushProvider* pushProvider() { return 0; }
 
-
     // navigator.connect --------------------------------------------------

[jkarlin, 2015/02/27 20:08:12]

Double vertical space here seems to be the norm. Add the deleted line back.

 
     virtual WebNavigatorConnectProvider* navigatorConnectProvider() { return 0; }
 
+    // Background Sync API------------------------------------------------------------
+
+    virtual WebSyncProvider* backgroundSyncProvider() { return 0; }
+
 protected:
     BLINK_PLATFORM_EXPORT Platform();
     virtual ~Platform() { }
 
     WebThread* m_mainThread;
 };
 
 } // namespace blink
 
 #endif