adb: search for a maximum of 16 emulators.

Android Wear has unfortunately been using port 5601 for years, which
falls into the range of ports we were previously polling for Android
emulators. Reduce the maximum number of emulators we can support so
that 5601 no longer falls within our range.

Bug: http://b/26468076
Change-Id: I931809cfa412122f4781eebe0164facab12c95f0
diff --git a/transport_local.cpp b/transport_local.cpp
index 4121f47..4f3e1f5 100644
--- a/transport_local.cpp
+++ b/transport_local.cpp
@@ -37,14 +37,19 @@
 #include "adb_utils.h"
 
 #if ADB_HOST
+
+// Android Wear has been using port 5601 in all of its documentation/tooling,
+// but we search for emulators on ports [5554, 5555 + ADB_LOCAL_TRANSPORT_MAX].
+// Avoid stomping on their port by limiting the number of emulators that can be
+// connected.
+#define ADB_LOCAL_TRANSPORT_MAX 16
+
+ADB_MUTEX_DEFINE(local_transports_lock);
+
 /* we keep a list of opened transports. The atransport struct knows to which
  * local transport it is connected. The list is used to detect when we're
  * trying to connect twice to a given local transport.
  */
-#define  ADB_LOCAL_TRANSPORT_MAX  64
-
-ADB_MUTEX_DEFINE( local_transports_lock );
-
 static atransport*  local_transports[ ADB_LOCAL_TRANSPORT_MAX ];
 #endif /* ADB_HOST */