Add field-initializing constructors to generated mojo structs.

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 039308b551b145ebeab8a3d64b0c119842925ec2..363ef7cdab78387f299674cb7a877cc504c4e461 100644
--- a/mojo/public/cpp/bindings/tests/wtf_types_unittest.cc
+++ b/mojo/public/cpp/bindings/tests/wtf_types_unittest.cc
@@ -158,9 +158,7 @@ TEST_F(WTFTypesTest, Serialization_WTFVectorToStlVector) {
 }
 
 TEST_F(WTFTypesTest, Serialization_PublicAPI) {
-  blink::TestWTFStructPtr input(blink::TestWTFStruct::New());
-  input->str = kHelloWorld;
-  input->integer = 42;
+  blink::TestWTFStructPtr input(blink::TestWTFStruct::New(kHelloWorld, 42));
 
   blink::TestWTFStructPtr cloned_input = input.Clone();