Add device_unittests target to linux_default_tests list.

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index e06db5fb9cc6eea59e5f261cccb1208a3fc2bd92..28ddae5e66607b8806485c402398cf9ad5b010bc 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -279,7 +279,6 @@ if (is_linux) {
     testonly = true
     deps = [
       # components_browsertests  TODO(GYP)
-      # device_unittests  TODO(GYP)
       # nacl_loader_unittests  TODO(GYP)
 
       "//base:base_unittests",  # PASSES (*) 2/25/2015
@@ -294,6 +293,7 @@ if (is_linux) {
       "//content/test:content_unittests",  # PASSES 2/25/2015
       "//crypto:crypto_unittests",  # PASSES 2/25/2015
       "//dbus:dbus_unittests",  # PASSES 2/25/2015
+      "//device:device_unittests",  # PASSES 3/07/2015
       "//extensions:extensions_browsertests",  # PASSES 2/25/2015
       "//extensions:extensions_unittests",  # PASSES 2/25/2015
       "//extensions/shell:app_shell_unittests",  # PASSES 2/25/2015