Mojo C++ bindings: make the generator use STL/WTF string/vector/map by default.

ipc/BUILD.gn

Index: ipc/BUILD.gn
diff --git a/ipc/BUILD.gn b/ipc/BUILD.gn
index d9998dba6a31dbb8be2d3489d68fbb1618cedead..85fcd84cc6e18d425b862b3d6467d2c51faf528c 100644
--- a/ipc/BUILD.gn
+++ b/ipc/BUILD.gn
@@ -165,6 +165,8 @@ mojom("mojom") {
   sources = [
     "ipc.mojom",
   ]
+
+  use_new_wrapper_types = false
 }
 
 mojom("test_interfaces") {
@@ -172,6 +174,8 @@ mojom("test_interfaces") {
   sources = [
     "ipc_test.mojom",
   ]
+
+  use_new_wrapper_types = false
 }
 
 # This is provided as a separate target so other targets can provide param