Fix the battery status API.

Battery status was crashing when called because the Java code in the
component was not being compiled into the webview in the android build
system. Add the missing java source directory. Battery status now works.
http://crbug.com/465366

Change-Id: I6e0f7d8d4bd0f8a284ac3e6a2a7c9e7ec1585f51
diff --git a/android_webview/java_library_common.mk b/android_webview/java_library_common.mk
index b5792ed..ee7bcc3 100644
--- a/android_webview/java_library_common.mk
+++ b/android_webview/java_library_common.mk
@@ -19,6 +19,7 @@
     ../net/android/java/src/org/chromium/net/IRemoteAndroidKeyStoreCallbacks.aidl \
     ../net/android/java/src/org/chromium/net/IRemoteAndroidKeyStore.aidl \
     $(call all-java-files-under, ../base/android/java/src) \
+    $(call all-java-files-under, ../device/battery/android/java/src) \
     $(call all-java-files-under, ../media/base/android/java/src) \
     $(call all-java-files-under, ../mojo/android/system/src) \
     $(call all-java-files-under, ../mojo/public/java/bindings/src) \