Add APIs to manage WriteBooster buffer

Five new APIs are introduced to manage and flush
UFS WriteBooster buffer.

Bug: 349648148
Test: StorageManager.*WriteBooster*
Change-Id: I2f82a2d8b08d83a63cbc3da4d9512792b0d472ba
Signed-off-by: Daniel Lee <chullee@google.com>
diff --git a/Android.bp b/Android.bp
index 1eeb1a1..f1221eb 100644
--- a/Android.bp
+++ b/Android.bp
@@ -143,6 +143,7 @@
         "VoldNativeServiceValidation.cpp",
         "VoldUtil.cpp",
         "VolumeManager.cpp",
+        "WriteBooster.cpp",
         "cryptfs.cpp",
         "fs/Exfat.cpp",
         "fs/Ext4.cpp",