Convert //cc from scoped_ptr to std::unique_ptr.

cc/trees/layer_tree_host_unittest_record_gpu_histogram.cc

Index: cc/trees/layer_tree_host_unittest_record_gpu_histogram.cc
diff --git a/cc/trees/layer_tree_host_unittest_record_gpu_histogram.cc b/cc/trees/layer_tree_host_unittest_record_gpu_histogram.cc
index 524013048361244ad2be91fcb57bafc325ea6f3e..f56109b077fa5a48813845f78feeefd84556a104 100644
--- a/cc/trees/layer_tree_host_unittest_record_gpu_histogram.cc
+++ b/cc/trees/layer_tree_host_unittest_record_gpu_histogram.cc
@@ -15,7 +15,7 @@ TEST(LayerTreeHostRecordGpuHistogramTest, SingleThreaded) {
   FakeLayerTreeHostClient host_client(FakeLayerTreeHostClient::DIRECT_3D);
   TestTaskGraphRunner task_graph_runner;
   LayerTreeSettings settings;
-  scoped_ptr<FakeLayerTreeHost> host =
+  std::unique_ptr<FakeLayerTreeHost> host =
       FakeLayerTreeHost::Create(&host_client, &task_graph_runner, settings,
                                 CompositorMode::SINGLE_THREADED);
   host->RecordGpuRasterizationHistogram();
@@ -26,7 +26,7 @@ TEST(LayerTreeHostRecordGpuHistogramTest, Threaded) {
   FakeLayerTreeHostClient host_client(FakeLayerTreeHostClient::DIRECT_3D);
   TestTaskGraphRunner task_graph_runner;
   LayerTreeSettings settings;
-  scoped_ptr<FakeLayerTreeHost> host = FakeLayerTreeHost::Create(
+  std::unique_ptr<FakeLayerTreeHost> host = FakeLayerTreeHost::Create(
       &host_client, &task_graph_runner, settings, CompositorMode::THREADED);
   host->RecordGpuRasterizationHistogram();
   EXPECT_TRUE(host->gpu_rasterization_histogram_recorded());