Decouple Power Monitor from //content.

content/test/BUILD.gn

Index: content/test/BUILD.gn
diff --git a/content/test/BUILD.gn b/content/test/BUILD.gn
index b320f411e787bdbd34f2abe750ba96343ded16ae..b05cab71229d2f2a964e5b7185c5927b785f841f 100644
--- a/content/test/BUILD.gn
+++ b/content/test/BUILD.gn
@@ -1137,7 +1137,6 @@ test("content_unittests") {
     "../browser/notifications/notification_id_generator_unittest.cc",
     "../browser/notifications/platform_notification_context_unittest.cc",
     "../browser/notifications/type_converters_unittest.cc",
-    "../browser/power_monitor_message_broadcaster_unittest.cc",
     "../browser/presentation/presentation_service_impl_unittest.cc",
     "../browser/presentation/presentation_type_converters_unittest.cc",
     "../browser/quota/mock_quota_manager.cc",
@@ -1257,7 +1256,6 @@ test("content_unittests") {
     "../child/indexed_db/webidbdatabase_impl_unittest.cc",
     "../child/memory/child_memory_coordinator_impl_unittest.cc",
     "../child/notifications/notification_data_conversions_unittest.cc",
-    "../child/power_monitor_broadcast_source_unittest.cc",
     "../child/resource_dispatcher_unittest.cc",
     "../child/service_worker/service_worker_dispatcher_unittest.cc",
     "../child/shared_memory_data_consumer_handle_unittest.cc",
@@ -1392,7 +1390,6 @@ test("content_unittests") {
     "//device/bluetooth:mocks",
     "//device/gamepad",
     "//device/gamepad:test_helpers",
-    "//device/power_monitor/public/interfaces",
     "//device/sensors/public/cpp",
     "//device/sensors/public/interfaces",
     "//gin",