Refactor device/BUILD.gn to list source files only once.

device/BUILD.gn

Index: device/BUILD.gn
diff --git a/device/BUILD.gn b/device/BUILD.gn
index 9c684ebbc895de1955c88efd27b227dbb179d28a..323cd0d65e8b7d4f30f2c1176e633931cdf263a3 100644
--- a/device/BUILD.gn
+++ b/device/BUILD.gn
@@ -5,9 +5,11 @@
 import("//build/config/features.gni")
 import("//testing/test.gni")
 
+is_linux_without_udev = is_linux && !use_udev
+is_linux_without_dbus = is_linux && !use_dbus
+
 test("device_unittests") {
   sources = [
-    "battery/battery_status_manager_linux_unittest.cc",
     "battery/battery_status_manager_win_unittest.cc",
     "battery/battery_status_service_unittest.cc",
     "bluetooth/bluetooth_adapter_mac_unittest.mm",
@@ -24,18 +26,8 @@ test("device_unittests") {
     "bluetooth/bluetooth_socket_chromeos_unittest.cc",
     "bluetooth/bluetooth_task_manager_win_unittest.cc",
     "bluetooth/bluetooth_uuid_unittest.cc",
-    "hid/hid_connection_unittest.cc",
-    "hid/hid_device_filter_unittest.cc",
-    "hid/hid_report_descriptor_unittest.cc",
-    "hid/input_service_linux_unittest.cc",
-    "hid/test_report_descriptors.cc",
-    "hid/test_report_descriptors.h",
     "nfc/nfc_chromeos_unittest.cc",
     "nfc/nfc_ndef_record_unittest.cc",
-    "serial/data_sink_unittest.cc",
-    "serial/data_source_unittest.cc",
-    "serial/serial_connection_unittest.cc",
-    "serial/serial_service_unittest.cc",
     "test/run_all_unittests.cc",
     "test/usb_test_gadget_impl.cc",
     "usb/usb_context_unittest.cc",
@@ -50,10 +42,7 @@ test("device_unittests") {
     "//device/battery",
     "//device/battery:mojo_bindings",
     "//device/bluetooth",
-    "//device/hid",
     "//device/nfc",
-    "//device/serial",
-    "//device/serial:test_support",
     "//device/usb",
     "//mojo/environment:chromium",
     "//net",
@@ -65,37 +54,14 @@ test("device_unittests") {
     "//url",
   ]
 
-  if (is_chromeos) {
-    sources -= [ "battery/battery_status_manager_linux_unittest.cc" ]
-
-    configs += [ "//build/config/linux:dbus" ]
-
-    deps += [
-      "//chromeos",
-      "//chromeos:test_support",
-      "//chromeos:test_support_without_gmock",
-      "//dbus",
-    ]
-  }
-
-  if (is_posix && !is_mac) {
-    libs = [ "rt" ]
-  }
-
-  if (is_mac) {
-    libs = [ "IOBluetooth.framework" ]
-  }
-
-  if (use_udev) {
-    sources += [ "udev_linux/udev_unittest.cc" ]
-
-    deps += [ "//device/udev_linux" ]
+  if (!is_linux_without_dbus && !is_chromeos) {
+    sources += [ "battery/battery_status_manager_linux_unittest.cc" ]
   }
 
-  if (is_linux && !use_udev) {
-    # Udev is the only Linux implementation. If we're compiling without Udev,
-    # disable these unittests.
-    sources -= [
+  # HID and Serial:
+  # Linux, requires udev.
+  if (!is_linux_without_udev) {
+    sources += [
       "hid/hid_connection_unittest.cc",
       "hid/hid_device_filter_unittest.cc",
       "hid/hid_report_descriptor_unittest.cc",
@@ -107,15 +73,34 @@ test("device_unittests") {
       "serial/serial_connection_unittest.cc",
       "serial/serial_service_unittest.cc",
     ]
-
-    deps -= [
+    deps += [
       "//device/hid",
       "//device/serial",
       "//device/serial:test_support",
     ]
   }
 
-  if (is_linux && !use_dbus) {
-    sources -= [ "battery/battery_status_manager_linux_unittest.cc" ]
+  if (use_udev) {
+    sources += [ "udev_linux/udev_unittest.cc" ]
+    deps += [ "//device/udev_linux" ]
+  }
+
+  if (is_chromeos) {
+    configs += [ "//build/config/linux:dbus" ]
+
+    deps += [
+      "//chromeos",
+      "//chromeos:test_support",
+      "//chromeos:test_support_without_gmock",
+      "//dbus",
+    ]
+  }
+
+  if (is_posix && !is_mac) {
+    libs = [ "rt" ]
+  }
+
+  if (is_mac) {
+    libs = [ "IOBluetooth.framework" ]
   }
 }