Create bootloader_message static library.

bootloader_messages merges bootloader_message_writer
and bootloader.cpp, so we can use the same library to
manage bootloader_message in normal boot and recovery mode.

Bug: 29582118

Change-Id: I9efdf776ef8f02b53911ff43a518e035e0c29618
(cherry picked from commit 2f272c0551f984e83bc5abaf240e0dddb38a3326)
diff --git a/Android.mk b/Android.mk
index 68f069d..2a3438f 100644
--- a/Android.mk
+++ b/Android.mk
@@ -41,7 +41,6 @@
 LOCAL_SRC_FILES := \
     adb_install.cpp \
     asn1_decoder.cpp \
-    bootloader.cpp \
     device.cpp \
     fuse_sdcard_provider.cpp \
     install.cpp \
@@ -75,6 +74,7 @@
 
 LOCAL_STATIC_LIBRARIES := \
     libbatterymonitor \
+    libbootloader_message \
     libext4_utils_static \
     libsparse_static \
     libziparchive \
@@ -150,14 +150,16 @@
 LOCAL_CFLAGS := -Werror
 include $(BUILD_STATIC_LIBRARY)
 
-include $(LOCAL_PATH)/minui/Android.mk \
-    $(LOCAL_PATH)/otautil/Android.mk \
+include \
+    $(LOCAL_PATH)/applypatch/Android.mk \
+    $(LOCAL_PATH)/bootloader_message/Android.mk \
+    $(LOCAL_PATH)/edify/Android.mk \
+    $(LOCAL_PATH)/minui/Android.mk \
     $(LOCAL_PATH)/minadbd/Android.mk \
+    $(LOCAL_PATH)/otafault/Android.mk \
+    $(LOCAL_PATH)/otautil/Android.mk \
     $(LOCAL_PATH)/tests/Android.mk \
     $(LOCAL_PATH)/tools/Android.mk \
-    $(LOCAL_PATH)/edify/Android.mk \
     $(LOCAL_PATH)/uncrypt/Android.mk \
-    $(LOCAL_PATH)/otafault/Android.mk \
     $(LOCAL_PATH)/updater/Android.mk \
     $(LOCAL_PATH)/update_verifier/Android.mk \
-    $(LOCAL_PATH)/applypatch/Android.mk