replace variant with any in variable.h, test=develop (#4000)

lite/core/variable.h

@@ -33,19 +33,19 @@ class Variable {
 
   template <typename T>
   T* GetMutable() {
-    if (!blob_.is<T>()) blob_.set<T>();
+    if (!blob_.valid()) {
+      blob_.set<T>();
+    }
     return blob_.get_mutable<T>();
   }
 
   template <typename T>
   bool IsType() {
-    return blob_.type() == typeid(T).hash_code();
+    return blob_.is_type<T>();
   }
 
  private:
-  // variant<int, float, std::string, lite::Tensor> blob_;
-  variant<int, float, std::string, lite::Tensor, std::vector<lite::Tensor>>
-      blob_;
+  Any blob_;
 };
 
 }  // namespace lite

lite/utils/any.h

@@ -62,6 +62,9 @@ class Any {
   template <typename T, typename... Args>
   inline void construct(Args&&... args);
 
+  template <typename T>
+  inline bool is_type() const;
+
  private:
   template <typename T>
   class TypeOnHeap;
@@ -214,6 +217,14 @@ inline const std::type_info& Any::type() const {
   }
 }
 
+template <typename T>
+inline bool Any::is_type() const {
+  if ((type_ == nullptr) || (*(type_->ptype_info) != typeid(T))) {
+    return false;
+  }
+  return true;
+}
+
 template <typename T>
 inline void Any::check_type() const {
   CHECK_EQ((type_ == nullptr), false);