Add purge all caches to our ashmem wrapper.

src/utils/android/ashmem.h

Index: src/utils/android/ashmem.h
diff --git a/src/utils/android/ashmem.h b/src/utils/android/ashmem.h
index 2d6c0b5a4742bcf3700486a16ac7a668b8745e60..278192b4399ec5fb946d7bba8db151a775159626 100644
--- a/src/utils/android/ashmem.h
+++ b/src/utils/android/ashmem.h
@@ -19,6 +19,7 @@ int ashmem_set_prot_region(int fd, int prot);
 int ashmem_pin_region(int fd, size_t offset, size_t len);
 int ashmem_unpin_region(int fd, size_t offset, size_t len);
 int ashmem_get_size_region(int fd);
+int ashmem_purge_all_caches(int fd);
 
 #ifdef __cplusplus
 }