Add src_files to src_jar GN template

url/BUILD.gn

Index: url/BUILD.gn
diff --git a/url/BUILD.gn b/url/BUILD.gn
index c6020fb1a2368be072c5b446891e9033411287d9..ee0fc5095de075cd262155241fc09cde6e4a1bc3 100644
--- a/url/BUILD.gn
+++ b/url/BUILD.gn
@@ -99,12 +99,21 @@ component("url") {
 
 if (is_android) {
   android_library("url_java") {
-    java_files = [ "android/java/src/org/chromium/url/IDNStringUtil.java" ]
+    srcjar_deps = [ ":url_java_srcjar" ]
     deps = [
       "//base:base_java",
     ]
   }
 
+  # Creates srcjar that contains sources for "url_java".
+  zip("url_java_srcjar") {
+    inputs = [
+      "android/java/src/org/chromium/url/IDNStringUtil.java",
+    ]
+    output = "$target_gen_dir/$target_name.srcjar"
+    base_dir = rebase_path("//url")
+  }
+
   generate_jni("url_jni_headers") {
     sources = [
       "android/java/src/org/chromium/url/IDNStringUtil.java",