Add absl dependency as needed

WORKSPACE

@@ -9,6 +9,13 @@ http_archive(
 )
 
 http_archive(
+    name = "com_google_absl",
+    sha256 = "f41868f7a938605c92936230081175d1eae87f6ea2c248f41077c8f88316f111",
+    strip_prefix = "abseil-cpp-20200225.2",
+    urls = ["https://github.com/abseil/abseil-cpp/archive/20200225.2.tar.gz"],
+)
+
+http_archive(
     name = "com_google_googletest",
     strip_prefix = "googletest-3f0cf6b62ad1eb50d8736538363d3580dd640c3e",
     urls = ["https://github.com/google/googletest/archive/3f0cf6b62ad1eb50d8736538363d3580dd640c3e.zip"],