Rewrite the Android implementation of BatteryMonitor directly in Java.

device/battery/BUILD.gn

Index: device/battery/BUILD.gn
diff --git a/device/battery/BUILD.gn b/device/battery/BUILD.gn
index 5a633743335bb73c2648ecc055f6849ee7898659..e3afef718bcf3d3fbab41e2e2c4ea6764ecd13ce 100644
--- a/device/battery/BUILD.gn
+++ b/device/battery/BUILD.gn
@@ -12,8 +12,6 @@ component("battery") {
     "battery_export.h",
     "battery_monitor_impl.cc",
     "battery_monitor_impl.h",
-    "battery_status_manager_android.cc",
-    "battery_status_manager_android.h",
     "battery_status_manager_chromeos.cc",
     "battery_status_manager_default.cc",
     "battery_status_manager_linux.cc",
@@ -36,15 +34,6 @@ component("battery") {
     "//mojo/edk/system",
   ]
 
-  if (is_android) {
-    deps += [ "//device/battery/android:battery_jni_headers" ]
-    sources += [
-      "android/battery_jni_registrar.h",
-      "android/battery_jni_registrar.cc",
-    ]
-    sources -= [ "battery_status_manager_default.cc" ]
-  }
-
   if (is_chromeos) {
     configs += [ "//build/config/linux:dbus" ]
     deps += [ "//chromeos:power_manager_proto" ]