Migrate WTF::HashMap::add() to ::insert()

mojo/public/cpp/bindings/tests/wtf_types_unittest.cc

Index: mojo/public/cpp/bindings/tests/wtf_types_unittest.cc
diff --git a/mojo/public/cpp/bindings/tests/wtf_types_unittest.cc b/mojo/public/cpp/bindings/tests/wtf_types_unittest.cc
index 9a20cc45a4b7cbea09a0199d03a6022dfd6e96cb..5551e450ef20f5a56169f1d5f68d5624663123b1 100644
--- a/mojo/public/cpp/bindings/tests/wtf_types_unittest.cc
+++ b/mojo/public/cpp/bindings/tests/wtf_types_unittest.cc
@@ -75,9 +75,9 @@ WTF::Vector<WTF::String> ConstructStringArray() {
 WTF::HashMap<WTF::String, WTF::String> ConstructStringMap() {
   WTF::HashMap<WTF::String, WTF::String> str_map;
   // A null string as value.
-  str_map.add("0", WTF::String());
-  str_map.add("1", kHelloWorld);
-  str_map.add("2", WTF::String::fromUTF8(kUTF8HelloWorld));
+  str_map.insert("0", WTF::String());
+  str_map.insert("1", kHelloWorld);
+  str_map.insert("2", WTF::String::fromUTF8(kUTF8HelloWorld));
 
   return str_map;
 }