Fix google-explicit-constructor warnings.

Bug: 28341362
Change-Id: I080090d50f1a368a4e7c1a0732297bb6a295e34f
diff --git a/libs/hwui/tests/microbench/TaskManagerBench.cpp b/libs/hwui/tests/microbench/TaskManagerBench.cpp
index c6b9f3b..cf47f273 100644
--- a/libs/hwui/tests/microbench/TaskManagerBench.cpp
+++ b/libs/hwui/tests/microbench/TaskManagerBench.cpp
@@ -29,7 +29,7 @@
 
 class TrivialProcessor : public TaskProcessor<char> {
 public:
-    TrivialProcessor(TaskManager* manager)
+    explicit TrivialProcessor(TaskManager* manager)
             : TaskProcessor(manager) {}
     virtual ~TrivialProcessor() {}
     virtual void onProcess(const sp<Task<char> >& task) override {