IDLCompiler: Do not add mixin's component to interface

Adding it misleads as if the interface is originally defined in core/.

For example, ServiceWorker is defined in modules, and includes a mixin
AbstractWorker which is defined in core.
Then ServiceWorker's |components| returns both core and modules.

This CL skips adding component information in merging mixins to prevent
such troubles.


Bug: 839389
Change-Id: I63dd8cdb3c75f56bfa5ba22d06042de42712b6ab
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2024230
Commit-Queue: Hitoshi Yoshida <peria@chromium.org>
Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#735760}

third_party/blink/renderer/bindings/scripts/web_idl/idl_compiler.py

@@ -316,7 +316,8 @@ class IdlCompiler(object):
             self._ir_map.add(new_ir)
             for ir in irs_to_be_merged:
                 to_be_merged = make_copy(ir)
-                new_ir.add_components(to_be_merged.components)
+                if new_ir.is_mixin == to_be_merged.is_mixin:
+                    new_ir.add_components(to_be_merged.components)
                 new_ir.debug_info.add_locations(
                     to_be_merged.debug_info.all_locations)
                 new_ir.attributes.extend(to_be_merged.attributes)