Add IntDefs to generated Java enums.

components/cronet/android/BUILD.gn

Index: components/cronet/android/BUILD.gn
diff --git a/components/cronet/android/BUILD.gn b/components/cronet/android/BUILD.gn
index c1e38706268a38a4c8b986bb5fbb13022dc0d215..e67d4b227bd97a97e30b362bbaa6a984e8aab176 100644
--- a/components/cronet/android/BUILD.gn
+++ b/components/cronet/android/BUILD.gn
@@ -57,6 +57,9 @@ java_cpp_enum("url_request_error_java") {
 # This target is a jar file containing classes that Cronet's javadocs
 # may reference but are not included in the javadocs themselves.
 android_library("cronet_javadoc_classpath") {
+  deps = [
+    "//third_party/android_tools:android_support_annotations_java",
+  ]
   srcjar_deps = [ ":url_request_error_java" ]
 }