Add IDL and initial Blink API for Background Sync

public/platform/Platform.h

Index: public/platform/Platform.h
diff --git a/public/platform/Platform.h b/public/platform/Platform.h
index 562aa1cc9017ff92c597bc1b64e3888c913f8974..35e1c27b84975c6498f123b0760e2e78ba314d21 100644
--- a/public/platform/Platform.h
+++ b/public/platform/Platform.h
@@ -60,6 +60,7 @@ class GrContext;
 namespace blink {
 
 class WebAudioBus;
+class WebSyncProvider;

[jkarlin, 2015/02/27 20:08:13]

not alphabetical. Part of me wonders if this should be
WebBackgroundSyncProvider.

[iclelland, 2015/03/02 03:51:12]

It's sort of alphabetical now (and yeah, I had it named
WebBackgroundSyncProvider originally, thus the out-of-place declaration.)

 class WebBlobRegistry;
 class WebBluetooth;
 class WebClipboard;
@@ -654,11 +655,14 @@ public:
 
     virtual WebPushProvider* pushProvider() { return 0; }
 
-

[jkarlin, 2015/02/27 20:08:13]

Add the line back, as is this file's strange custom

[iclelland, 2015/03/02 03:51:12]

Done.

     // navigator.connect --------------------------------------------------
 
     virtual WebNavigatorConnectProvider* navigatorConnectProvider() { return 0; }
 
+    // Background Sync API------------------------------------------------------------
+
+    virtual WebSyncProvider* backgroundSyncProvider() { return 0; }
+
 protected:
     BLINK_PLATFORM_EXPORT Platform();
     virtual ~Platform() { }