bind-gen: Implement property installation of IDL interface

Bug: 839389
Change-Id: I9225b87e94f3719e043908bd351a4c8777fd40ba
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1971651Reviewed-by: Hitoshi Yoshida <peria@chromium.org>
Commit-Queue: Yuki Shiino <yukishiino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#727149}

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

@@ -645,7 +645,7 @@ class SymbolScopeNode(SequenceNode):
             assert did_insert
         elif counts[DIRECT_CHILD_SCOPES] == 1:
             pass  # Let the child SymbolScopeNode do the work.
-        elif counts[Likeliness.LIKELY] >= 2:
+        elif counts[Likeliness.ALWAYS] + counts[Likeliness.LIKELY] >= 2:
             did_insert = insert_before_threshold(self, Likeliness.LIKELY)
             assert did_insert
         else:

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

@@ -21,6 +21,7 @@ class CodeGenContext(object):
 
     # "for_world" attribute values
     MAIN_WORLD = "main"
+    NON_MAIN_WORLDS = "other"
     ALL_WORLDS = "all"
 
     @classmethod

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

@@ -94,6 +94,16 @@ class Exposure(object):
             return False
         return self._only_in_secure_contexts
 
+    @property
+    def is_context_dependent(self):
+        """
+        Returns True if the exposure of this construct depends on a context.
+        """
+        return bool(self.global_names_and_features
+                    or self.context_dependent_runtime_enabled_features
+                    or self.context_enabled_features
+                    or self.only_in_secure_contexts)
+
 
 class ExposureMutable(Exposure):
     def __init__(self):