Remove parts of //cc we aren't using

cc/base/BUILD.gn

Index: cc/base/BUILD.gn
diff --git a/cc/base/BUILD.gn b/cc/base/BUILD.gn
index 203f84add5ecc9c2adb8e9d36d1c2fb0a130b188..b9a803c355ac1d39669c7eb91bc0a517b8a6a36b 100644
--- a/cc/base/BUILD.gn
+++ b/cc/base/BUILD.gn
@@ -6,31 +6,15 @@ source_set("base") {
   visibility = [ "//cc" ]
 
   sources = [
+    "blocking_task_runner.cc",
+    "blocking_task_runner.h",
     "completion_event.h",
-    "delayed_unique_notifier.cc",
-    "delayed_unique_notifier.h",
-    "invalidation_region.cc",
-    "invalidation_region.h",
     "math_util.cc",
     "math_util.h",
-    "ref_counted_managed.h",
-    "region.cc",
-    "region.h",
-    "rolling_time_delta_history.cc",
-    "rolling_time_delta_history.h",
-    "scoped_ptr_algorithm.h",
     "scoped_ptr_deque.h",
     "scoped_ptr_vector.h",
-    "simple_enclosed_region.cc",
-    "simple_enclosed_region.h",
     "switches.cc",
     "switches.h",
-    "synced_property.h",
-    "tiling_data.cc",
-    "tiling_data.h",
-    "time_util.h",
-    "unique_notifier.cc",
-    "unique_notifier.h",
     "util.h",
   ]