[Android] Fix gn build for instrumentation tests.

tools/android/common/BUILD.gn

Index: tools/android/common/BUILD.gn
diff --git a/tools/android/common/BUILD.gn b/tools/android/common/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..8307a91e8c186280d2d65e5869e6389f9b3697d1
--- /dev/null
+++ b/tools/android/common/BUILD.gn
@@ -0,0 +1,15 @@
+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# GYP: //tools/android/common/common.gyp:android_tools_common
+source_set("common") {
+  sources = [
+    "adb_connection.cc",
+    "adb_connection.h",
+    "daemon.cc",
+    "daemon.h",
+    "net.cc",
+    "net.h",
+  ]
+}