Add missing 'explicit's on single-argument constructors.

Change-Id: I1494df6e74ec16238971fb4346ba184eb61c37ab
diff --git a/src/compiled_method.h b/src/compiled_method.h
index e228ca8..1a5c34d 100644
--- a/src/compiled_method.h
+++ b/src/compiled_method.h
@@ -70,7 +70,7 @@
 
 class CompiledInvokeStub {
  public:
-  CompiledInvokeStub(std::vector<uint8_t>& code);
+  explicit CompiledInvokeStub(std::vector<uint8_t>& code);
   ~CompiledInvokeStub();
   const std::vector<uint8_t>& GetCode() const;
  private: