Give ScopedJavaGlobalRef copy and assignment constructors

base/android/scoped_java_ref.h

Index: base/android/scoped_java_ref.h
diff --git a/base/android/scoped_java_ref.h b/base/android/scoped_java_ref.h
index e15ad661e2d85f34a129c5a0a674cc2b847ff94f..da5a020eaa4b53cfabf6b04926727b2292a5f899 100644
--- a/base/android/scoped_java_ref.h
+++ b/base/android/scoped_java_ref.h
@@ -227,7 +227,7 @@ class ScopedJavaGlobalRef : public JavaRef<T> {
  public:
   ScopedJavaGlobalRef() {}
 
-  explicit ScopedJavaGlobalRef(const ScopedJavaGlobalRef<T>& other) {
+  ScopedJavaGlobalRef(const ScopedJavaGlobalRef<T>& other) {
     this->Reset(other);
   }
 
@@ -242,6 +242,12 @@ class ScopedJavaGlobalRef : public JavaRef<T> {
     this->Reset();
   }
 
+  // Overloaded assignment operator defined for consistency with the implicit
+  // copy constructor.
+  void operator=(const ScopedJavaGlobalRef<T>& other) {
+    this->Reset(other);
+  }
+
   void Reset() {
     this->ResetGlobalRef();
   }