Data usage label width, locking, Wi-Fi fixes.

Avoid wrapping sweep labels when underlying string is long, and avoid
showing blank "^1" sweep labels.  Only offer "restrict data" when
mobile networks are present.  Add locking around UidDetailProvider.

Move to isNetworkSupported() for consistency.

Bug: 5492495, 5471602, 5439402, 5373465
Change-Id: I79f5938d45ffbb4c2c242106424a466042a26c1c

src/com/android/settings/net/UidDetailProvider.java

@@ -39,14 +39,14 @@ public class UidDetailProvider {
         mUidDetailCache = new SparseArray<UidDetail>();
     }
 
-    public void clearCache() {
+    public synchronized void clearCache() {
         mUidDetailCache.clear();
     }
 
     /**
      * Resolve best descriptive label for the given UID.
      */
-    public UidDetail getUidDetail(int uid, boolean blocking) {
+    public synchronized UidDetail getUidDetail(int uid, boolean blocking) {
         final UidDetail cached = mUidDetailCache.get(uid);
         if (cached != null) {
             return cached;