Initial implementation of WifiScanner

This change implements basic functionality of WifiScanner. Following
functionality is enabled

1. Scanning - specify a list of channels to scan
2. Significant change detection
3. AP hotlist

Change-Id: Ieef75b96bdbbd3c7d9b9e698bd16e64d3b465254
diff --git a/services/java/com/android/server/SystemServer.java b/services/java/com/android/server/SystemServer.java
index 9305bc4..716823c 100644
--- a/services/java/com/android/server/SystemServer.java
+++ b/services/java/com/android/server/SystemServer.java
@@ -650,6 +650,15 @@
                 }
 
                 try {
+                    Slog.i(TAG, "Wi-Fi Scanning Service");
+                    mSystemServiceManager.startService(
+                            "com.android.server.wifi.WifiScanningService");
+
+                } catch (Throwable e) {
+                    reportWtf("starting Wi-Fi Scanning Service", e);
+                }
+
+                try {
                     Slog.i(TAG, "Connectivity Service");
                     connectivity = new ConnectivityService(
                             context, networkManagement, networkStats, networkPolicy);