Refactored Shell to use IDumpstateListener.

BugreportProgressService used to poll system properties to get the
progress of the underlying dumpstate process, but now dumpstate provides
a IDumpstateListener and IDumpstateToken binder objects for the same
purpose.

Test: BugreportReceiverTest passes
Test: manual verification

BUG: 31636879

Change-Id: I81d551781a511cb1cc218a27452875b0bb267f7a
diff --git a/Android.mk b/Android.mk
index bd04214..ef67e8f 100644
--- a/Android.mk
+++ b/Android.mk
@@ -487,7 +487,7 @@
 	../../system/update_engine/binder_bindings/android/os/IUpdateEngine.aidl \
 	../../system/update_engine/binder_bindings/android/os/IUpdateEngineCallback.aidl \
 
-LOCAL_SRC_FILES +=  \
+LOCAL_SRC_FILES += \
 	../../system/netd/server/binder/android/net/INetd.aidl \
 
 LOCAL_AIDL_INCLUDES += system/update_engine/binder_bindings