Remove unnecessary `explicit` qualifiers on constructors.

Change-Id: Id12e392ad50f66a6e2251a68662b7959315dc567
diff --git a/compiler/dex/pass_driver_me.h b/compiler/dex/pass_driver_me.h
index cbe4a02..d0af71c 100644
--- a/compiler/dex/pass_driver_me.h
+++ b/compiler/dex/pass_driver_me.h
@@ -36,7 +36,7 @@
 
 class PassDriverME: public PassDriver {
  public:
-  explicit PassDriverME(const PassManager* const pass_manager, CompilationUnit* cu)
+  PassDriverME(const PassManager* const pass_manager, CompilationUnit* cu)
       : PassDriver(pass_manager), pass_me_data_holder_(), dump_cfg_folder_("/sdcard/") {
         pass_me_data_holder_.bb = nullptr;
         pass_me_data_holder_.c_unit = cu;
@@ -314,4 +314,3 @@
 };
 }  // namespace art
 #endif  // ART_COMPILER_DEX_PASS_DRIVER_ME_H_
-