Convert FieldTrialList to Accept a std::unique_ptr

chrome/browser/autocomplete/search_provider_unittest.cc

Index: chrome/browser/autocomplete/search_provider_unittest.cc
diff --git a/chrome/browser/autocomplete/search_provider_unittest.cc b/chrome/browser/autocomplete/search_provider_unittest.cc
index c04160cc3d45997c88434264f4a70a61bf00a801..72a669a8703777f4e84a88d65de70012346b6a72 100644
--- a/chrome/browser/autocomplete/search_provider_unittest.cc
+++ b/chrome/browser/autocomplete/search_provider_unittest.cc
@@ -508,7 +508,7 @@ void SearchProviderTest::ResetFieldTrialList() {
   // a DCHECK.
   field_trial_list_.reset();
   field_trial_list_.reset(new base::FieldTrialList(
-      new metrics::SHA1EntropyProvider("foo")));
+      base::MakeUnique<metrics::SHA1EntropyProvider>("foo")));

[Alexei Svitkine (slow), 2016/09/21 15:52:00]

Nit: Actually all the test code that currently passes in an entropy provider
should just work if null is passed. So I suggest cleaning that up while you're
touching all these places. (should apply to all tests currently doing something
like this)

[robliao, 2016/09/21 17:24:29]

I haven't done an analysis of the tests to verify that this behavior is okay.

This CL shouldn't trigger any new behaviors since it's a signature change, so we
can do that in a followup CL if need be.

   variations::testing::ClearAllVariationParams();
 }