Refactored gamepad polling to support dynamic sources

device/gamepad/BUILD.gn

 # Copyright 2016 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.
 
 import("//build/config/features.gni")
 
 if (is_android) {
   import("//build/config/android/config.gni")
   import("//build/config/android/rules.gni")  # For generate_jni().
 }
 
 component("gamepad") {
   output_name = "device_gamepad"
 
   sources = [
     "gamepad_consumer.cc",
     "gamepad_consumer.h",
     "gamepad_data_fetcher.cc",
     "gamepad_data_fetcher.h",
+    "gamepad_data_fetcher_manager.cc",
+    "gamepad_data_fetcher_manager.h",
     "gamepad_platform_data_fetcher.h",
     "gamepad_platform_data_fetcher_android.cc",
     "gamepad_platform_data_fetcher_android.h",
     "gamepad_platform_data_fetcher_linux.cc",
     "gamepad_platform_data_fetcher_linux.h",
     "gamepad_platform_data_fetcher_mac.h",
     "gamepad_platform_data_fetcher_mac.mm",
     "gamepad_platform_data_fetcher_win.cc",
     "gamepad_platform_data_fetcher_win.h",
     "gamepad_provider.cc",
     "gamepad_provider.h",
     "gamepad_standard_mappings.cc",
     "gamepad_standard_mappings.h",
     "gamepad_standard_mappings_linux.cc",
     "gamepad_standard_mappings_mac.mm",
     "gamepad_standard_mappings_win.cc",
     "gamepad_user_gesture.cc",
     "gamepad_user_gesture.h",
     "raw_input_data_fetcher_win.cc",
     "raw_input_data_fetcher_win.h",
-    "xbox_data_fetcher_mac.cc",
     "xbox_data_fetcher_mac.h",
+    "xbox_data_fetcher_mac.mm",
   ]
 
   deps = [
     "//base",
     "//base/third_party/dynamic_annotations",
     "//third_party/WebKit/public:blink_headers",
   ]
 
   defines = [ "DEVICE_GAMEPAD_IMPLEMENTATION" ]
 
   if (is_win) {
     cflags = [ "/wd4267" ]  # conversion from 'size_t' (64 bit) to 'type'(32 bit).
   }
 
   if (is_linux && use_udev) {
     deps += [ "//device/udev_linux" ]
   } else if (!is_win && !is_mac && !is_android) {
-    sources += [ "gamepad_platform_data_fetcher.cc" ]
     sources -= [ "gamepad_platform_data_fetcher_linux.cc" ]
   }
 
   if (is_android) {
     deps += [ ":jni_headers" ]
   }
 
   if (is_mac) {
     libs = [
       "CoreFoundation.framework",
@@ skipping 37 matching lines @@
     ]
     srcjar_deps = [ ":java_enums_srcjar" ]
   }
 
   java_cpp_enum("java_enums_srcjar") {
     sources = [
       "gamepad_standard_mappings.h",
     ]
   }
 }