libbrillo: 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: Ic83227a7ddbbad32a1df1f9554d29470c1a2dd42
Reviewed-on: https://chromium-review.googlesource.com/905784
Commit-Ready: Eric Caruso <ejcaruso@chromium.org>
Tested-by: Eric Caruso <ejcaruso@chromium.org>
Reviewed-by: Dan Erat <derat@chromium.org>
diff --git a/brillo/key_value_store_unittest.cc b/brillo/key_value_store_unittest.cc
index cd18e89..68875ef 100644
--- a/brillo/key_value_store_unittest.cc
+++ b/brillo/key_value_store_unittest.cc
@@ -40,8 +40,9 @@
 TEST_F(KeyValueStoreTest, LoadAndSaveFromFile) {
   base::ScopedTempDir temp_dir_;
   CHECK(temp_dir_.CreateUniqueTempDir());
-  base::FilePath temp_file_ = temp_dir_.path().Append("temp.conf");
-  base::FilePath saved_temp_file_ = temp_dir_.path().Append("saved_temp.conf");
+  base::FilePath temp_file_ = temp_dir_.GetPath().Append("temp.conf");
+  base::FilePath saved_temp_file_ =
+      temp_dir_.GetPath().Append("saved_temp.conf");
 
   string blob = "A=B\n# Comment\n";
   ASSERT_EQ(blob.size(), base::WriteFile(temp_file_, blob.data(), blob.size()));