Fix sim build (sim doesn't have strl*() reliably...)

Just stub out the TrafficStats code for the sim.
Bug: 2578938

Change-Id: Ie555f67f581d05ee446ea29cb2223feb350c52f9

core/jni/android_net_TrafficStats.cpp

@@ -32,6 +32,7 @@ namespace android {
 
 // Returns an ASCII decimal number read from the specified file, -1 on error.
 static jlong readNumber(char const* filename) {
+#ifdef HAVE_ANDROID_OS
     char buf[80];
     int fd = open(filename, O_RDONLY);
     if (fd < 0) {
@@ -49,6 +50,9 @@ static jlong readNumber(char const* filename) {
     close(fd);
     buf[len] = '\0';
     return atoll(buf);
+#else  // Simulator
+    return -1;
+#endif
 }
 
 // Return the number from the first file which exists and contains data
@@ -60,6 +64,7 @@ static jlong tryBoth(char const* a, char const* b) {
 // Returns the sum of numbers from the specified path under /sys/class/net/*,
 // -1 if no such file exists.
 static jlong readTotal(char const* suffix) {
+#ifdef HAVE_ANDROID_OS
     char filename[PATH_MAX] = "/sys/class/net/";
     DIR *dir = opendir(filename);
     if (dir == NULL) {
@@ -81,6 +86,9 @@ static jlong readTotal(char const* suffix) {
 
     closedir(dir);
     return total;
+#else  // Simulator
+    return -1;
+#endif
 }
 
 // Mobile stats get accessed a lot more often than total stats.