Remove external begin frame source parameter and settings

cc/debug/micro_benchmark_controller_unittest.cc

Index: cc/debug/micro_benchmark_controller_unittest.cc
diff --git a/cc/debug/micro_benchmark_controller_unittest.cc b/cc/debug/micro_benchmark_controller_unittest.cc
index 5853118283fd9bc72615d8d004907e60304333d9..998677758058804fadf26fcb4b187eb4f7d3b42e 100644
--- a/cc/debug/micro_benchmark_controller_unittest.cc
+++ b/cc/debug/micro_benchmark_controller_unittest.cc
@@ -35,7 +35,7 @@ class MicroBenchmarkControllerTest : public testing::Test {
     layer_tree_host_->SetRootLayer(Layer::Create());
     layer_tree_host_->InitializeForTesting(
         TaskRunnerProvider::Create(nullptr, nullptr),
-        std::unique_ptr<Proxy>(new FakeProxy), nullptr);
+        std::unique_ptr<Proxy>(new FakeProxy));
   }
 
   void TearDown() override {