CodeGen: Make blink_type_info work for buffer source types

This is to unblock compilations, and not to work for all the cases
that use buffer source types.

And adds an assertion to show a clear message that an unknown type is
passed in the function. (Otherwise, we may hit a property access error
on None objects.)


Bug: 839389
Change-Id: I98e54356e7dafd98a93023afc220700913b5d6f2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1965779
Commit-Queue: Hitoshi Yoshida <peria@chromium.org>
Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#724511}

third_party/blink/renderer/bindings/scripts/bind_gen/blink_v8_bridge.py

@@ -81,6 +81,14 @@ def blink_type_info(idl_type):
     if real_type.is_string:
         return TypeInfo("String", ref_fmt="{}&", is_nullable=True)
 
+    if real_type.is_buffer_source_type:
+        return TypeInfo(
+            'DOM{}'.format(real_type.keyword_typename),
+            member_fmt="Member<{}>",
+            ref_fmt="{}*",
+            value_fmt="{}*",
+            is_nullable=True)
+
     if real_type.is_symbol:
         assert False, "Blink does not support/accept IDL symbol type."
 
@@ -129,6 +137,8 @@ def blink_type_info(idl_type):
         return TypeInfo(
             "base::Optional<{}>".format(inner_type.value_t), ref_fmt="{}&")
 
+    assert False, "Unknown type: {}".format(idl_type.syntactic_form)
+
 
 def native_value_tag(idl_type):
     """Returns the tag type of NativeValueTraits."""