bind-gen: Implement make_overload_dispatcher

Implements the core part of overload resolution.

Bug: 839389
Change-Id: If1281a7df2f4adf08968f6b361c5d43ef5999a87
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1906453Reviewed-by: Hitoshi Yoshida <peria@chromium.org>
Commit-Queue: Yuki Shiino <yukishiino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#719534}

third_party/blink/renderer/bindings/scripts/generate_bindings.pydeps

@@ -35,6 +35,7 @@ bind_gen/clang_format.py
 bind_gen/code_node.py
 bind_gen/codegen_accumulator.py
 bind_gen/codegen_context.py
+bind_gen/codegen_expr.py
 bind_gen/codegen_utils.py
 bind_gen/dictionary.py
 bind_gen/interface.py

third_party/blink/renderer/bindings/scripts/web_idl/demonstration_and_testing.idl

@@ -20,7 +20,11 @@
 namespace TestNamespace {
   [RaisesException] readonly attribute Promise<boolean> attr1;
   readonly attribute TestInterfaceConstructor attr2;
-  void op1(long x, boolean y, TestInterfaceConstructor z);
+  void op1(long x, TestInterfaceConstructor z, boolean y);
+  void op1(long x, optional DOMString y, optional ExampleDictionary z);
+  [RuntimeEnabled=TestFeature1] void op1(boolean... x);
+  [RuntimeEnabled=TestFeature2] void op1(long x, ArrayBuffer... xx);
+  [RuntimeEnabled=TestFeature2] void op1(long x, DataView... xx);
 };
 
 dictionary ExampleDictionary {