update_engine: use ScopedTempDir::GetPath

Upstream versions of libchrome have gotten rid of ScopedTempDir's
inline path method because they wanted to introduce a DCHECK that
helps make sure people create the temp directory before using it.
To avoid introducing a header dependency on the logging header
they took this method out of the header so it wouldn't be inlined.

BUG=b:37434548
TEST=unit tests

Change-Id: If1dcc5e43f54ab32fd43da7b939216a4834548d5
Reviewed-on: https://chromium-review.googlesource.com/882543
Commit-Ready: Eric Caruso <ejcaruso@chromium.org>
Tested-by: Eric Caruso <ejcaruso@chromium.org>
Reviewed-by: Amin Hassani <ahassani@chromium.org>
diff --git a/omaha_response_handler_action_unittest.cc b/omaha_response_handler_action_unittest.cc
index 60b139b..13e2e93 100644
--- a/omaha_response_handler_action_unittest.cc
+++ b/omaha_response_handler_action_unittest.cc
@@ -334,7 +334,7 @@
 
   OmahaRequestParams params(&fake_system_state_);
   fake_system_state_.fake_hardware()->SetIsOfficialBuild(false);
-  params.set_root(tempdir.path().value());
+  params.set_root(tempdir.GetPath().value());
   params.set_current_channel("canary-channel");
   // The ImageProperties in Android uses prefs to store MutableImageProperties.
 #ifdef __ANDROID__
@@ -369,7 +369,7 @@
 
   OmahaRequestParams params(&fake_system_state_);
   fake_system_state_.fake_hardware()->SetIsOfficialBuild(false);
-  params.set_root(tempdir.path().value());
+  params.set_root(tempdir.GetPath().value());
   params.set_current_channel("stable-channel");
   // The ImageProperties in Android uses prefs to store MutableImageProperties.
 #ifdef __ANDROID__