Roll Fuchsia SDK from e237df60615b to c9b6deebf8ef.

This is a manual roll to bring us to the most-recent working SDK build.

CQ_INCLUDE_TRYBOTS=luci.chromium.try:fuchsia_arm64_cast_audio;luci.chromium.try:fuchsia_x64_cast_audio


Change-Id: I1c614558bc5b3f2376537455d42fb705e5ce3dee
Reviewed-on: https://chromium-review.googlesource.com/1141929
Reviewed-by: Nico Weber <thakis@chromium.org>
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Sergey Ulanov <sergeyu@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Commit-Queue: Sergey Ulanov <sergeyu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#576199}

CrOS-Libchrome-Original-Commit: 3d18716cca8b7fd1fdfdbe7d50bb74116a30d489
diff --git a/base/environment_unittest.cc b/base/environment_unittest.cc
index 23aec51..7cb8c9c 100644
--- a/base/environment_unittest.cc
+++ b/base/environment_unittest.cc
@@ -16,7 +16,13 @@
 
 namespace {
 
+// PATH env variable is not set on Fuchsia by default, while PWD is not set on
+// Windows.
+#if defined(OS_FUCHSIA)
+constexpr char kValidEnvironmentVariable[] = "PWD";
+#else
 constexpr char kValidEnvironmentVariable[] = "PATH";
+#endif
 
 }  // namespace