Limit the size of latency info storage

cc/surfaces/display.h

Index: cc/surfaces/display.h
diff --git a/cc/surfaces/display.h b/cc/surfaces/display.h
index b96abb6fe5d74cb14f8e16dd5509d226d4e06bff..428b241f44c844d07cc77389bb7a292608347cbd 100644
--- a/cc/surfaces/display.h
+++ b/cc/surfaces/display.h
@@ -87,6 +87,9 @@ class CC_SURFACES_EXPORT Display : public DisplaySchedulerClient,
 
   bool has_scheduler() const { return !!scheduler_; }
   DirectRenderer* renderer_for_testing() const { return renderer_.get(); }
+  size_t stored_latency_info_size_for_testing() const {
+    return stored_latency_info_.size();
+  }
 
   void ForceImmediateDrawAndSwapIfPossible();