replace 'new String()' with ""

bug reported by findbugs
http://b/issue?id=1856909

core/java/android/webkit/BrowserFrame.java

@@ -685,7 +685,7 @@ class BrowserFrame extends Handler {
 
             default:
                 Log.e(LOGTAG, "getRawResFilename got incompatible resource ID");
-                return new String();
+                return "";
         }
         TypedValue value = new TypedValue();
         mContext.getResources().getValue(resid, value, true);

core/java/android/webkit/CacheManager.java

@@ -429,7 +429,7 @@ public final class CacheManager {
         if (checkCacheRedirect(cacheRet.httpStatusCode)) {
             // location is in database, no need to keep the file
             cacheRet.contentLength = 0;
-            cacheRet.localPath = new String();
+            cacheRet.localPath = "";
             cacheRet.outFile.delete();
         } else if (cacheRet.contentLength == 0) {
             cacheRet.outFile.delete();