[remoting android] Add and build host code.

remoting/host/username.cc

Index: remoting/host/username.cc
diff --git a/remoting/host/username.cc b/remoting/host/username.cc
index 712a1555e473f2803a60c3e2c55fffa974d16443..507c8e15274d046c4e99a2188a2e9cc331e12389 100644
--- a/remoting/host/username.cc
+++ b/remoting/host/username.cc
@@ -18,7 +18,9 @@
 namespace remoting {
 
 std::string GetUsername() {
-#if defined(OS_POSIX)
+#if defined(OS_ANDROID)
+  return std::string();

[Sergey Ulanov, 2016/04/07 00:56:14]

I don't think you need to separate this from the case at the end. Change the if
statement to defined(OS_POSIX) && !defined(OS_ANDROID).

[Lambros, 2016/04/12 21:58:04]

Done.

+#elif defined(OS_POSIX)
   long buf_size = sysconf(_SC_GETPW_R_SIZE_MAX);
   if (buf_size <= 0)
     return std::string();