adb: implement zstd compression for file sync.

Bug: http://b/150827486
Test: test_device.py
Change-Id: I9fac4c760d9dbdce0b3b883db975cfa9b27a9e80
diff --git a/adb/client/commandline.cpp b/adb/client/commandline.cpp
index eaa32e5..43772ba 100644
--- a/adb/client/commandline.cpp
+++ b/adb/client/commandline.cpp
@@ -1336,6 +1336,8 @@
         return CompressionType::Brotli;
     } else if (str == "lz4") {
         return CompressionType::LZ4;
+    } else if (str == "zstd") {
+        return CompressionType::Zstd;
     }
 
     error_exit("unexpected compression type %s", str.c_str());