IDL: Improve "argument needs v8::TryCatch" logic slightly

Enumeration types are effectively strings, and should thus be handled the
same, meaning they don't need a v8::TryCatch object.

This changes generated code for a few methods that take at least one
enumeration type argument, and don't otherwise need a v8::TryCatch, by
eliminating the unnecessary v8::TryCatch locals.

Also refactor slightly: pass in the IdlOperation object and check whether
the return type is Promise inside argument_needs_try_catch(), instead
of passing in that fact as an argument. This keeps the logic localized in
argument_needs_try_catch().

R=haraken@chromium.org
BUG=

Review URL: https://codereview.chromium.org/482713002

git-svn-id: svn://svn.chromium.org/blink/trunk@180459 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/bindings/scripts/v8_interface.py

@@ -856,7 +856,7 @@ def sort_and_groupby(l, key=None):
 
 # [Constructor]
 def constructor_context(interface, constructor):
-    arguments_need_try_catch = any(v8_methods.argument_needs_try_catch(argument, return_promise=False)
+    arguments_need_try_catch = any(v8_methods.argument_needs_try_catch(constructor, argument)
                                    for argument in constructor.arguments)
 
     # [RaisesException=Constructor]

third_party/WebKit/Source/bindings/scripts/v8_methods.py

@@ -52,11 +52,12 @@ CUSTOM_REGISTRATION_EXTENDED_ATTRIBUTES = frozenset([
 ])
 
 
-def argument_needs_try_catch(argument, return_promise):
+def argument_needs_try_catch(method, argument):
+    return_promise = method.idl_type and method.idl_type.name == 'Promise'
     idl_type = argument.idl_type
     base_type = idl_type.base_type
 
-    return not (
+    return not(
         # These cases are handled by separate code paths in the
         # generate_argument() macro in Source/bindings/templates/methods.cpp.
         idl_type.is_callback_interface or
@@ -65,7 +66,8 @@ def argument_needs_try_catch(argument, return_promise):
         # String and enumeration arguments converted using one of the
         # TOSTRING_* macros except for _PROMISE variants in
         # Source/bindings/core/v8/V8BindingMacros.h don't use a v8::TryCatch.
-        (base_type == 'DOMString' and not argument.is_variadic and
+        ((base_type == 'DOMString' or idl_type.is_enum) and
+         not argument.is_variadic and
          not return_promise))
 
 
@@ -85,7 +87,6 @@ def method_context(interface, method):
     idl_type = method.idl_type
     is_static = method.is_static
     name = method.name
-    return_promise = idl_type.name == 'Promise'
 
     idl_type.add_includes_for_type()
     this_cpp_value = cpp_value(interface, method, len(arguments))
@@ -126,7 +127,7 @@ def method_context(interface, method):
     is_raises_exception = 'RaisesException' in extended_attributes
 
     arguments_need_try_catch = (
-        any(argument_needs_try_catch(argument, return_promise)
+        any(argument_needs_try_catch(method, argument)
             for argument in arguments))
 
     return {

third_party/WebKit/Source/bindings/tests/results/V8TestObject.cpp

@@ -6652,8 +6652,6 @@ static void voidMethodTestEnumArgMethod(const v8::FunctionCallbackInfo<v8::Value
     TestObject* impl = V8TestObject::toNative(info.Holder());
     V8StringResource<> testEnumTypeArg;
     {
-        v8::TryCatch block;
-        V8RethrowTryCatchScope rethrow(block);
         TOSTRING_VOID_INTERNAL(testEnumTypeArg, info[0]);
         String string = testEnumTypeArg;
         if (!(string == "" || string == "EnumValue1" || string == "EnumValue2" || string == "EnumValue3")) {