bind-gen: Simplify SymbolNode's constructor

Makes SymbolNode's constructor easy to call.  It turned out that
most callers will pass simple template text.

Bug: 839389
Change-Id: Id27031efbbb5b216866c38a62fb805349652b380
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1862596
Commit-Queue: Yuki Shiino <yukishiino@chromium.org>
Reviewed-by: Hitoshi Yoshida <peria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#706527}

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

@@ -386,20 +386,42 @@ class SymbolNode(CodeNode):
     will be automatically inserted iff this symbol is referenced.
     """
 
-    def __init__(self, name, definition_node_constructor):
+    def __init__(self,
+                 name,
+                 template_text=None,
+                 definition_node_constructor=None):
         """
         Args:
             name: The name of this code symbol.
+            template_text: Template text to be used to define the code symbol.
             definition_node_constructor: A callable that creates and returns a
-                new definition node.  This node will be passed as the argument.
+                new definition node.  This SymbolNode will be passed as the
+                argument.
+                Either of |template_text| or |definition_node_constructor| must
+                be given.
         """
         assert isinstance(name, str) and name
-        assert callable(definition_node_constructor)
+        assert (template_text is not None
+                or definition_node_constructor is not None)
+        assert template_text is None or definition_node_constructor is None
+        if template_text is not None:
+            assert isinstance(template_text, str)
+        if definition_node_constructor is not None:
+            assert callable(definition_node_constructor)
 
         CodeNode.__init__(self)
 
         self._name = name
-        self._definition_node_constructor = definition_node_constructor
+
+        if template_text is not None:
+
+            def constructor(symbol_node):
+                return SymbolDefinitionNode(
+                    symbol_node, template_text=template_text)
+
+            self._definition_node_constructor = constructor
+        else:
+            self._definition_node_constructor = definition_node_constructor
 
     def _render(self, renderer, last_render_state):
         if not renderer.last_caller.is_code_symbol_defined(self):
@@ -460,7 +482,7 @@ class SymbolScopeNode(SequenceNode):
     """
 
     def _render(self, renderer, last_render_state):
-        # Sort nodes in order to generate reproducible code.
+        # Sort nodes in order to render reproducible results.
         symbol_nodes = sorted(
             last_render_state.code_symbols_used.itervalues(),
             key=lambda symbol_node: symbol_node.name)

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

@@ -7,7 +7,6 @@ import unittest
 from .code_node import LiteralNode
 from .code_node import SequenceNode
 from .code_node import SimpleNode
-from .code_node import SymbolDefinitionNode
 from .code_node import SymbolNode
 from .code_node import SymbolScopeNode
 from .mako_renderer import MakoRenderer
@@ -83,20 +82,12 @@ class CodeNodeTest(unittest.TestCase):
         renderer = MakoRenderer()
         root = SymbolScopeNode(renderer=renderer)
 
-        def make_symbol(name, template_text):
-            def constructor(symbol_node):
-                return SymbolDefinitionNode(
-                    symbol_node, template_text=template_text)
-
-            return SymbolNode(
-                name=name, definition_node_constructor=constructor)
-
         root.register_code_symbols([
-            make_symbol("var1", "int var1 = ${var2} + ${var3};"),
-            make_symbol("var2", "int var2 = ${var5};"),
-            make_symbol("var3", "int var3 = ${var4};"),
-            make_symbol("var4", "int var4 = 1;"),
-            make_symbol("var5", "int var5 = 2;"),
+            SymbolNode("var1", "int var1 = ${var2} + ${var3};"),
+            SymbolNode("var2", "int var2 = ${var5};"),
+            SymbolNode("var3", "int var3 = ${var4};"),
+            SymbolNode("var4", "int var4 = 1;"),
+            SymbolNode("var5", "int var5 = 2;"),
         ])
 
         root.append(SimpleNode(template_text="(void)${var1};"))

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

@@ -21,19 +21,11 @@ def run_example(web_idl_database, output_dirs):
         code_node.SimpleNode(template_text="print ${z};"),
     ])
 
-    def make_symbol(name, template_text):
-        def constructor(symbol_node):
-            return code_node.SymbolDefinitionNode(
-                symbol_node, template_text=template_text)
-
-        return code_node.SymbolNode(
-            name=name, definition_node_constructor=constructor)
-
-    root_node.add_template_vars({
-        'x': make_symbol('x', "int ${x} = 1;"),
-        'y': make_symbol('y', "int ${y} = 2;"),
-        'z': make_symbol('z', "int ${z};"),
-    })
+    root_node.register_code_symbols([
+        code_node.SymbolNode('x', "int ${x} = 1;"),
+        code_node.SymbolNode('y', "int ${y} = 2;"),
+        code_node.SymbolNode('z', "int ${z};"),
+    ])
 
     prev = ''
     current = str(root_node)