Set up a FeatureList instance for unit tests.

This way, code that uses the FeatureList API that runs
as part of unit tests won't hit a DCHECK that a FeatureList
doesn't exist.

In a follow-up CL, I plan to expand this a bit to add support
for tests overriding default feature state. But would like to land
this initial version first, as it unblock a couple of early adopters
of this API.

BUG=548289

Review URL: https://codereview.chromium.org/1416503004

Cr-Commit-Position: refs/heads/master@{#356477}

1 files changed, 1 insertions, 0 deletions

diff --git a/base/feature_list_unittest.cc b/base/feature_list_unittest.cc
index 9d8538e..cb8f744 100644
--- a/base/feature_list_unittest.cc
+++ b/base/feature_list_unittest.cc
@@ -33,6 +33,7 @@ class FeatureListTest : public testing::Test {
   ~FeatureListTest() override { ClearFeatureListInstance(); }
 
   void RegisterFeatureListInstance(scoped_ptr<FeatureList> feature_list) {
+    FeatureList::ClearInstanceForTesting();
     feature_list_ = feature_list.get();
     FeatureList::SetInstance(feature_list.Pass());
   }