chromeos: Add support for the battery status API on chromeos.

content/content_browser.gypi

Index: content/content_browser.gypi
diff --git a/content/content_browser.gypi b/content/content_browser.gypi
index 1422f74f907b912a7550c53a026abaecc3e8c6f1..1638873fa4ab946a7848244f80300f2e1fa3a4fb 100644
--- a/content/content_browser.gypi
+++ b/content/content_browser.gypi
@@ -29,6 +29,7 @@
   'sources': [
     'port/browser/render_widget_host_view_port.h',
     'public/browser/access_token_store.h',
+    'public/browser/battery_status_provider.h',
     'public/browser/browser_accessibility_state.h',
     'public/browser/browser_child_process_host.h',
     'public/browser/browser_child_process_host_delegate.cc',
@@ -102,6 +103,7 @@
     'public/browser/plugin_data_remover.h',
     'public/browser/plugin_service_filter.h',
     'public/browser/plugin_service.h',
+    'public/browser/power_supply_status.h',
     'public/browser/profiler_controller.h',
     'public/browser/profiler_subscriber.h',
     'public/browser/quota_permission_context.h',
@@ -180,6 +182,10 @@
     'browser/appcache/appcache_frontend_proxy.h',
     'browser/appcache/chrome_appcache_service.cc',
     'browser/appcache/chrome_appcache_service.h',
+    'browser/battery_status/battery_status_message_filter.cc',
+    'browser/battery_status/battery_status_message_filter.h',
+    'browser/battery_status/battery_status_provider_impl.cc',
+    'browser/battery_status/battery_status_provider_impl.h',
     'browser/browser_child_process_host_impl.cc',
     'browser/browser_child_process_host_impl.h',
     'browser/browser_context.cc',