Revert of Revert of IDL: Support optional argument default value syntax...

Revert of Revert of IDL: Support optional argument default value syntax (https://codereview.chromium.org/339683002/)

Reason for revert:
Revert the revert because the bot went green even without this revert, and other bots had no trouble.

Original issue's description:
> Revert of IDL: Support optional argument default value syntax (https://codereview.chromium.org/312683005/)
> 
> Reason for revert:
> This patch is the most likely candidate for browser test failures: http://build.chromium.org/p/chromium.webkit/builders/Linux%20Tests%20%28dbg%29/builds/2905
> 
> BrowserTestBase signal handler received SIGTERM. Backtrace:
> #0 0x7f2c2a201a1d base::debug::StackTrace::StackTrace()
> #1 0x00000460caf2 content::(anonymous namespace)::DumpStackTraceSignalHandler()
> #2 0x7f2c232cd4a0 \u003Cunknown>
> #3 0x7f2c2337f313 __poll
> #4 0x7f2c240b6036 \u003Cunknown>
> #5 0x7f2c240b6164 g_main_context_iteration
> #6 0x7f2c2a1c9b45 base::MessagePumpGlib::Run()
> #7 0x7f2c2a29eed7 base::MessageLoop::RunHandler()
> #8 0x7f2c2a2f69d8 base::RunLoop::Run()
> #9 0x00000466bd59 content::RunThisRunLoop()
> #10 0x00000466c1b8 content::MessageLoopRunner::Run()
> #11 0x000004610946 content::TitleWatcher::WaitAndGetTitle()
> #12 0x0000011fdf00 MediaBrowserTest::RunTest()
> #13 0x0000011fdc00 MediaBrowserTest::RunMediaTestPage()
> #14 0x0000011ec98b EncryptedMediaTestBase::RunEncryptedMediaTestPage()
> #15 0x0000011ee5fa EncryptedMediaTest::TestConfigChange()
> #16 0x0000011eb73a EncryptedMediaTest_ConfigChangeVideo_Test::RunTestOnMainThread()
> ...
> 
> Please look into it. An alterate possible candidate is  https://codereview.chromium.org/327553002 but I think that's less likely.
> 
> Original issue's description:
> > IDL: Support optional argument default value syntax
> > 
> > Adds support for parsing default values of different types, but
> > only handles null default values when generating code.
> > 
> > Replaces existing
> > 
> >   [Default=Null] optional SomeInterface arg
> >   [Default=NullString] optional DOMString arg
> > 
> > with the now equivalent
> > 
> >   optional SomeInterface arg = null
> >   optional DOMString arg = null
> > 
> > in IDL files, and drops support for those [Default] attributes.
> > 
> > No changes to generated code.
> > 
> > BUG=258153
> > 
> > Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=176200
> 
> TBR=nbarth@chromium.org,haraken@chromium.org,pavan.e@samsung.com,jsbell@chromium.org,jl@opera.com
> NOTREECHECKS=true
> NOTRY=true
> BUG=258153
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=176220

TBR=nbarth@chromium.org,haraken@chromium.org,pavan.e@samsung.com,jsbell@chromium.org,jl@opera.com
NOTREECHECKS=true
NOTRY=true
BUG=258153

Review URL: https://codereview.chromium.org/339723002

git-svn-id: svn://svn.chromium.org/blink/trunk@176231 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/bindings/IDLExtendedAttributes.txt

@@ -46,7 +46,7 @@ ConstructorCallWith=ExecutionContext|Document
 Custom=|Getter|Setter|LegacyCallAsFunction|ToV8|VisitDOMWrapper|Wrap|PropertyGetter|PropertyEnumerator|PropertyQuery
 CustomConstructor
 CustomElementCallbacks
-Default=Null|NullString|Undefined
+Default=Undefined
 DependentLifetime
 DeprecateAs=*
 DoNotCheckConstants

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

@@ -393,6 +393,59 @@ class IdlConstant(TypedObject):
             self.extended_attributes = {}
 
 
+################################################################################
+# Literals
+################################################################################
+
+class IdlLiteral(object):
+    def __init__(self, idl_type, value):
+        self.idl_type = idl_type
+        self.value = value
+        self.is_null = False
+
+    def __str__(self):
+        if self.idl_type == 'DOMString':
+            return 'String("%s")' % self.value
+        if self.idl_type == 'integer':
+            return '%d' % self.value
+        if self.idl_type == 'float':
+            return '%g' % self.value
+        if self.idl_type == 'boolean':
+            return 'true' if self.value else 'false'
+        raise ValueError('Unsupported literal type: %s' % self.idl_type)
+
+
+class IdlLiteralNull(IdlLiteral):
+    def __init__(self):
+        self.idl_type = 'NULL'
+        self.value = None
+        self.is_null = True
+
+    def __str__(self):
+        return 'nullptr'
+
+
+def default_node_to_idl_literal(node):
+    # FIXME: This code is unnecessarily complicated due to the rather
+    # inconsistent way the upstream IDL parser outputs default values.
+    # http://crbug.com/374178
+    idl_type = node.GetProperty('TYPE')
+    if idl_type == 'DOMString':
+        value = node.GetProperty('NAME')
+        if '"' in value or '\\' in value:
+            raise ValueError('Unsupported string value: %r' % value)
+        return IdlLiteral(idl_type, value)
+    if idl_type == 'integer':
+        return IdlLiteral(idl_type, int(node.GetProperty('NAME')))
+    if idl_type == 'float':
+        return IdlLiteral(idl_type, float(node.GetProperty('VALUE')))
+    if idl_type == 'boolean':
+        return IdlLiteral(idl_type, node.GetProperty('VALUE'))
+    if idl_type == 'NULL':
+        return IdlLiteralNull()
+    raise ValueError('Unrecognized default value type: %s' % idl_type)
+
+
 ################################################################################
 # Operations
 ################################################################################
@@ -475,6 +528,7 @@ class IdlArgument(TypedObject):
         self.is_optional = node.GetProperty('OPTIONAL')  # syntax: (optional T)
         self.is_variadic = False  # syntax: (T...)
         self.name = node.GetName()
+        self.default_value = None
 
         children = node.GetChildren()
         for child in children:
@@ -488,6 +542,8 @@ class IdlArgument(TypedObject):
                 if child_name != '...':
                     raise ValueError('Unrecognized Argument node; expected "...", got "%s"' % child_name)
                 self.is_variadic = child.GetProperty('ELLIPSIS') or False
+            elif child_class == 'Default':
+                self.default_value = default_node_to_idl_literal(child)
             else:
                 raise ValueError('Unrecognized node class: %s' % child_class)
 

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

@@ -181,8 +181,11 @@ def generate_argument(interface, method, argument, index):
                                            used_as_argument=True,
                                            used_as_variadic_argument=argument.is_variadic),
         'cpp_value': this_cpp_value,
+        # FIXME: check that the default value's type is compatible with the argument's
+        'default_value': str(argument.default_value) if argument.default_value else None,
         'enum_validation_expression': idl_type.enum_validation_expression,
-        'has_default': 'Default' in extended_attributes,
+        # FIXME: remove once [Default] removed and just use argument.default_value
+        'has_default': 'Default' in extended_attributes or argument.default_value,
         'has_event_listener_argument': any(
             argument_so_far for argument_so_far in method.arguments[:index]
             if argument_so_far.idl_type.name == 'EventListener'),
@@ -298,9 +301,10 @@ def v8_value_to_local_cpp_value(argument, index):
     name = argument.name
     if argument.is_variadic:
         return v8_value_to_local_cpp_variadic_value(argument, index)
-    # [Default=NullString]
+    # FIXME: This special way of handling string arguments with null defaults
+    # can go away once we fully support default values.
     if (argument.is_optional and idl_type.name in ('String', 'ByteString') and
-        extended_attributes.get('Default') == 'NullString'):
+        argument.default_value and argument.default_value.is_null):
         v8_value = 'argumentOrNull(info, %s)' % index
     else:
         v8_value = 'info[%s]' % index

third_party/WebKit/Source/bindings/tests/idls/TestInterfaceConstructor2.idl

@@ -44,7 +44,7 @@
         TestInterfaceEmpty testInterfaceEmptyArg,
         long longArg,
         [Default=Undefined] optional DOMString defaultUndefinedOptionalStringArg,
-        [Default=NullString] optional DOMString defaultNullStringOptionalStringArg,
+        optional DOMString defaultNullStringOptionalStringArg = null,
         [Default=Undefined] optional Dictionary defaultUndefinedOptionalDictionaryArg,
         optional DOMString optionalStringArg),
 ] interface TestInterfaceConstructor2 {

third_party/WebKit/Source/bindings/tests/idls/TestInterfaceNamedConstructor.idl

@@ -33,7 +33,7 @@
         [Default=Undefined] optional boolean defaultUndefinedOptionalBooleanArg,
         [Default=Undefined] optional long defaultUndefinedOptionalLongArg,
         [Default=Undefined] optional DOMString defaultUndefinedOptionalStringArg,
-        [Default=NullString] optional DOMString defaultNullStringOptionalstringArg,
+        optional DOMString defaultNullStringOptionalstringArg = null,
         optional DOMString optionalStringArg),
     RaisesException=Constructor,
 ] interface TestInterfaceNamedConstructor {

third_party/WebKit/Source/bindings/tests/idls/TestObject.idl

@@ -379,6 +379,16 @@ interface TestObject {
     // Optional arguments: exceptional case
     void voidMethodOptionalDictionaryArg(optional Dictionary optionalDictionaryArg);
 
+    // Optional arguments with defaults
+    void voidMethodDefaultStringArg(optional DOMString defaultStringArg = "foo");
+    void voidMethodDefaultNullStringArg(optional DOMString defaultStringArg = null);
+    void voidMethodDefaultLongArg(optional long defaultLongArg = 10);
+    void voidMethodDefaultDoubleArg(optional double defaultDoubleArg = 0.5);
+    void voidMethodDefaultTrueBooleanArg(optional boolean defaultBooleanArg = true);
+    void voidMethodDefaultFalseBooleanArg(optional boolean defaultBooleanArg = false);
+    void voidMethodDefaultNullableStringArg(optional DOMString? defaultStringArg = null);
+    void voidMethodDefaultNullableTestInterfaceArg(optional TestInterface? defaultTestInterfaceArg = null);
+
     // Variadic operations
     void voidMethodVariadicStringArg(DOMString... variadicStringArgs);
     void voidMethodStringArgVariadicStringArg(DOMString stringArg, DOMString... variadicStringArgs);
@@ -401,7 +411,7 @@ interface TestObject {
     void overloadedMethodF(optional DOMString stringArg);
     void overloadedMethodF(double doubleArg);
     void overloadedMethodG(long longArg);
-    void overloadedMethodG([Default=Null] TestInterfaceEmpty? testInterfaceEmptyOrNullArg);
+    void overloadedMethodG(optional TestInterfaceEmpty? testInterfaceEmptyOrNullArg = null);
     void overloadedMethodH(TestInterface testInterfaceArg);
     void overloadedMethodH(TestInterfaceEmpty testInterfaceEmptyArg);
     void overloadedMethodI(DOMString stringArg);
@@ -422,7 +432,6 @@ interface TestObject {
     void voidMethodDefaultUndefinedTestInterfaceEmptyArg([Default=Undefined] optional TestInterfaceEmpty defaultUndefinedTestInterfaceEmptyArg);
     void voidMethodDefaultUndefinedLongArg([Default=Undefined] optional long defaultUndefinedLongArg);
     void voidMethodDefaultUndefinedStringArg([Default=Undefined] optional DOMString defaultUndefinedStringArg);
-    void voidMethodDefaultNullStringStringArg([Default=NullString] optional DOMString defaultNullStringStringArg);
     // [EnforceRange]
     void voidMethodEnforceRangeLongArg([EnforceRange] long enforceRangeLongArg);
     // [TreatNullAs], [TreatUndefinedAs]

third_party/WebKit/Source/bindings/v8/V8Binding.cpp

@@ -494,7 +494,7 @@ float toFloat(v8::Handle<v8::Value> value, ExceptionState& exceptionState)
 
 String toByteString(v8::Handle<v8::Value> value, ExceptionState& exceptionState)
 {
-    // Handle [Default=NullString]
+    // Handle null default value.
     if (value.IsEmpty())
         return String();
 

third_party/WebKit/Source/core/css/CSSStyleDeclaration.idl

@@ -30,7 +30,7 @@
     [TreatReturnedNullStringAs=Null] DOMString          getPropertyPriority([Default=Undefined] optional DOMString propertyName);
      [RaisesException] void setProperty([Default=Undefined] optional DOMString propertyName,
                                     [TreatNullAs=NullString,Default=Undefined] optional DOMString value,
-                                    [TreatNullAs=NullString,Default=NullString] optional DOMString priority);
+                                    [TreatNullAs=NullString] optional DOMString priority = null);
 
     readonly attribute unsigned long    length;
     getter DOMString          item([Default=Undefined] optional unsigned long index);

third_party/WebKit/Source/core/css/FontFaceSet.idl

@@ -41,8 +41,8 @@ enum FontFaceSetLoadStatus { "loading", "loaded" };
     attribute EventHandler onloadingdone;
     attribute EventHandler onloadingerror;
 
-    [RaisesException] boolean check(DOMString font, [Default=NullString] optional DOMString text);
-    [CallWith=ScriptState] Promise load(DOMString font, [Default=NullString] optional DOMString text);
+    [RaisesException] boolean check(DOMString font, optional DOMString text = null);
+    [CallWith=ScriptState] Promise load(DOMString font, optional DOMString text = null);
     [CallWith=ScriptState] Promise ready();
 
     [RaisesException] void add(FontFace fontFace);

third_party/WebKit/Source/core/css/WebKitCSSMatrix.idl

@@ -25,7 +25,7 @@
 
 // Introduced in DOM Level ?:
 [
-    Constructor([Default=NullString] optional DOMString cssValue),
+    Constructor(optional DOMString cssValue = null),
     ImplementedAs=CSSMatrix,
     RaisesException=Constructor,
     WillBeGarbageCollected

third_party/WebKit/Source/core/dom/Comment.idl

@@ -18,7 +18,7 @@
  */
 
 [
-    Constructor([Default=NullString] optional DOMString data),
+    Constructor(optional DOMString data = null),
     ConstructorCallWith=Document,
 ] interface Comment : CharacterData {
 };

third_party/WebKit/Source/core/dom/DOMError.idl

@@ -26,7 +26,7 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 [
-    Constructor(DOMString name, [Default=NullString] optional DOMString message),
+    Constructor(DOMString name, optional DOMString message = null),
     WillBeGarbageCollected
 ] interface DOMError {
     readonly attribute DOMString name;

third_party/WebKit/Source/core/dom/DOMImplementation.idl

@@ -39,5 +39,5 @@
 
     // HTMLDOMImplementation interface from DOM Level 2 HTML
 
-    HTMLDocument createHTMLDocument([Default=NullString] optional DOMString title);
+    HTMLDocument createHTMLDocument(optional DOMString title = null);
 };

third_party/WebKit/Source/core/dom/Text.idl

@@ -17,7 +17,7 @@
  * Boston, MA 02110-1301, USA.
  */
 [
-    Constructor([Default=NullString] optional DOMString data),
+    Constructor(optional DOMString data = null),
     ConstructorCallWith=Document,
     Custom=Wrap,
 ] interface Text : CharacterData {

third_party/WebKit/Source/core/frame/ConsoleBase.idl

@@ -42,17 +42,17 @@
     [CallWith=ScriptArguments&ScriptState] void trace();
     [CallWith=ScriptArguments&ScriptState, ImplementedAs=assertCondition] void assert([Default=Undefined] optional boolean condition);
     [CallWith=ScriptArguments&ScriptState] void count();
-    [DeprecateAs=ConsoleMarkTimeline] void markTimeline([Default=NullString] optional DOMString title);
+    [DeprecateAs=ConsoleMarkTimeline] void markTimeline(optional DOMString title = null);
 
-    [CallWith=ScriptState] void profile([Default=NullString] optional DOMString title);
-    [CallWith=ScriptState] void profileEnd([Default=NullString] optional DOMString title);
+    [CallWith=ScriptState] void profile(optional DOMString title = null);
+    [CallWith=ScriptState] void profileEnd(optional DOMString title = null);
 
-    void time([Default=NullString] optional DOMString title);
-    [CallWith=ScriptState] void timeEnd([Default=NullString] optional DOMString title);
-    void timeStamp([Default=NullString] optional DOMString title);
+    void time(optional DOMString title = null);
+    [CallWith=ScriptState] void timeEnd(optional DOMString title = null);
+    void timeStamp(optional DOMString title = null);
 
-    [CallWith=ScriptState] void timeline([Default=NullString] optional DOMString title);
-    [CallWith=ScriptState] void timelineEnd([Default=NullString] optional DOMString title);
+    [CallWith=ScriptState] void timeline(optional DOMString title = null);
+    [CallWith=ScriptState] void timelineEnd(optional DOMString title = null);
 
     [CallWith=ScriptArguments&ScriptState] void group();
     [CallWith=ScriptArguments&ScriptState] void groupCollapsed();

third_party/WebKit/Source/core/frame/Window.idl

@@ -69,9 +69,9 @@
 
     void alert();
     void alert(DOMString message);
-    boolean confirm([Default=NullString] optional DOMString message);
-    [TreatReturnedNullStringAs=Null] DOMString prompt([Default=NullString] optional DOMString message,
-                                                      [Default=NullString] optional DOMString defaultValue);
+    boolean confirm(optional DOMString message = null);
+    [TreatReturnedNullStringAs=Null] DOMString prompt(optional DOMString message = null,
+                                                      optional DOMString defaultValue = null);
 
     boolean find([Default=Undefined] optional DOMString string,
                  [Default=Undefined] optional boolean caseSensitive,

third_party/WebKit/Source/core/html/HTMLAudioElement.idl

@@ -25,6 +25,6 @@
 
 [
     RuntimeEnabled=Media,
-    NamedConstructor=Audio([Default=NullString] optional DOMString src)
+    NamedConstructor=Audio(optional DOMString src = null)
 ] interface HTMLAudioElement : HTMLMediaElement {
 };

third_party/WebKit/Source/core/html/HTMLDialogElement.idl

@@ -28,7 +28,7 @@
 ] interface HTMLDialogElement : HTMLElement {
     [Reflect] attribute boolean open;
     attribute DOMString returnValue;
-    [RaisesException] void close([Default=NullString] optional DOMString returnValue);
+    [RaisesException] void close(optional DOMString returnValue = null);
     void show();
     [RaisesException] void showModal();
 };

third_party/WebKit/Source/core/html/HTMLInputElement.idl

@@ -85,7 +85,7 @@ interface HTMLInputElement : HTMLElement {
     [RaisesException] void setRangeText(DOMString replacement,
                         unsigned long start,
                         unsigned long end,
-                        [Default=NullString] optional DOMString selectionMode);
+                        optional DOMString selectionMode = null);
 
     [RaisesException, ImplementedAs=setSelectionRangeForBinding]
     void setSelectionRange([Default=Undefined] optional long start,

third_party/WebKit/Source/core/html/HTMLOptionElement.idl

@@ -19,7 +19,10 @@
  */
 
 [
-    NamedConstructor=Option([Default=NullString] optional DOMString data, [Default=NullString] optional DOMString value, [Default=Undefined] optional boolean defaultSelected, [Default=Undefined] optional boolean selected),
+    NamedConstructor=Option(optional DOMString data = null,
+                            optional DOMString value = null,
+                            [Default=Undefined] optional boolean defaultSelected,
+                            [Default=Undefined] optional boolean selected),
     RaisesException=Constructor
 ] interface HTMLOptionElement : HTMLElement {
     [Reflect] attribute boolean disabled;

third_party/WebKit/Source/core/html/HTMLSelectElement.idl

@@ -38,7 +38,7 @@ interface HTMLSelectElement : HTMLElement {
     getter Element item(unsigned long index);
     Element namedItem([Default=Undefined] optional DOMString name);
     // FIXME: should be union type http://crbug.com/240176
-    [RaisesException, TypeChecking=Interface] void add(HTMLElement element, [Default=Null] optional HTMLElement? before);
+    [RaisesException, TypeChecking=Interface] void add(HTMLElement element, optional HTMLElement? before = null);
     [ImplementedAs=addBeforeOptionAtIndex, RaisesException, TypeChecking=Interface] void add(HTMLElement element, long before);
     [RaisesException] void remove(); // ChildNode overload
     void remove(long index);

third_party/WebKit/Source/core/html/HTMLTextAreaElement.idl

@@ -56,7 +56,7 @@ interface HTMLTextAreaElement : HTMLElement {
     [RaisesException] void setRangeText(DOMString replacement,
                         unsigned long start,
                         unsigned long end,
-                        [Default=NullString] optional DOMString selectionMode);
+                        optional DOMString selectionMode = null);
 
     void setSelectionRange([Default=Undefined] optional long start,
                            [Default=Undefined] optional long end,

third_party/WebKit/Source/core/testing/TypeConversions.idl

@@ -48,5 +48,5 @@
 
     attribute ByteString testByteString;
     void setTestByteString(ByteString byteString);
-    [ImplementedAs=setTestByteString] void setTestByteStringDefaultNull([Default=NullString] optional ByteString byteString);
+    [ImplementedAs=setTestByteString] void setTestByteStringDefaultNull(optional ByteString byteString = null);
 };

third_party/WebKit/Source/core/timing/Performance.idl

@@ -39,7 +39,7 @@
 
     [MeasureAs=UnprefixedPerformanceTimeline] sequence<PerformanceEntry> getEntries();
     [MeasureAs=UnprefixedPerformanceTimeline] sequence<PerformanceEntry> getEntriesByType(DOMString entryType);
-    [MeasureAs=UnprefixedPerformanceTimeline] sequence<PerformanceEntry> getEntriesByName(DOMString name, [Default=NullString] optional DOMString entryType);
+    [MeasureAs=UnprefixedPerformanceTimeline] sequence<PerformanceEntry> getEntriesByName(DOMString name, optional DOMString entryType = null);
 
     [MeasureAs=PrefixedPerformanceClearResourceTimings] void webkitClearResourceTimings();
     [MeasureAs=PrefixedPerformanceSetResourceTimingBufferSize] void webkitSetResourceTimingBufferSize(unsigned long maxSize);
@@ -48,10 +48,10 @@
 
     // See http://www.w3.org/TR/2012/CR-user-timing-20120726/
     [RaisesException,MeasureAs=UnprefixedUserTiming] void mark(DOMString markName);
-    [MeasureAs=UnprefixedUserTiming] void clearMarks([Default=NullString] optional  DOMString markName);
+    [MeasureAs=UnprefixedUserTiming] void clearMarks(optional DOMString markName = null);
 
-    [RaisesException,MeasureAs=UnprefixedUserTiming] void measure(DOMString measureName, [Default=NullString] optional DOMString startMark, [Default=NullString] optional DOMString endMark);
-    [MeasureAs=UnprefixedUserTiming] void clearMeasures([Default=NullString] optional DOMString measureName);
+    [RaisesException,MeasureAs=UnprefixedUserTiming] void measure(DOMString measureName, optional DOMString startMark = null, optional DOMString endMark = null);
+    [MeasureAs=UnprefixedUserTiming] void clearMeasures(optional DOMString measureName = null);
 
     // See http://www.w3.org/TR/hr-time/ for details.
     double now();

third_party/WebKit/Source/core/workers/SharedWorker.idl

@@ -31,7 +31,7 @@
 
 [
     ActiveDOMObject,
-    Constructor(DOMString scriptURL, [Default=NullString] optional DOMString name),
+    Constructor(DOMString scriptURL, optional DOMString name = null),
     ConstructorCallWith=ExecutionContext,
     RaisesException=Constructor,
     RuntimeEnabled=SharedWorker,

third_party/WebKit/Source/modules/encoding/TextDecoder.idl

@@ -31,7 +31,7 @@
 [
     RuntimeEnabled=EncodingAPI,
     Exposed=Window&Worker,
-    Constructor([Default=NullString] optional DOMString label, optional Dictionary options),
+    Constructor(optional DOMString label = null, optional Dictionary options),
     RaisesException=Constructor,
     GarbageCollected,
     MeasureAs=TextDecoderConstructor

third_party/WebKit/Source/modules/encoding/TextEncoder.idl

@@ -31,11 +31,11 @@
 [
     RuntimeEnabled=EncodingAPI,
     Exposed=Window&Worker,
-    Constructor([Default=NullString] optional DOMString utfLabel),
+    Constructor(optional DOMString utfLabel = null),
     RaisesException=Constructor,
     GarbageCollected,
     MeasureAs=TextEncoderConstructor
 ] interface TextEncoder {
     readonly attribute DOMString encoding;
-    [MeasureAs=TextEncoderEncode] Uint8Array encode([Default=NullString] optional DOMString input, optional Dictionary options);
+    [MeasureAs=TextEncoderEncode] Uint8Array encode(optional DOMString input = null, optional Dictionary options);
 };

third_party/WebKit/Source/modules/encryptedmedia/HTMLMediaElementEncryptedMedia.idl

@@ -4,8 +4,8 @@
 
 partial interface HTMLMediaElement {
     [RuntimeEnabled=PrefixedEncryptedMedia, RaisesException, MeasureAs=PrefixedMediaGenerateKeyRequest] void webkitGenerateKeyRequest([TreatNullAs=NullString, TreatUndefinedAs=NullString] DOMString keySystem, optional Uint8Array initData);
-    [RuntimeEnabled=PrefixedEncryptedMedia, RaisesException, MeasureAs=PrefixedMediaAddKey] void webkitAddKey([TreatNullAs=NullString, TreatUndefinedAs=NullString] DOMString keySystem, Uint8Array key, optional Uint8Array initData, [Default=NullString] optional DOMString sessionId);
-    [RuntimeEnabled=PrefixedEncryptedMedia, RaisesException, MeasureAs=PrefixedMediaCancelKeyRequest] void webkitCancelKeyRequest([TreatNullAs=NullString, TreatUndefinedAs=NullString] DOMString keySystem, [Default=NullString] optional DOMString sessionId);
+    [RuntimeEnabled=PrefixedEncryptedMedia, RaisesException, MeasureAs=PrefixedMediaAddKey] void webkitAddKey([TreatNullAs=NullString, TreatUndefinedAs=NullString] DOMString keySystem, Uint8Array key, optional Uint8Array initData, optional DOMString sessionId = null);
+    [RuntimeEnabled=PrefixedEncryptedMedia, RaisesException, MeasureAs=PrefixedMediaCancelKeyRequest] void webkitCancelKeyRequest([TreatNullAs=NullString, TreatUndefinedAs=NullString] DOMString keySystem, optional DOMString sessionId = null);
 
     [RuntimeEnabled=PrefixedEncryptedMedia] attribute EventHandler onwebkitkeyadded;
     [RuntimeEnabled=PrefixedEncryptedMedia] attribute EventHandler onwebkitkeyerror;

third_party/WebKit/Source/modules/encryptedmedia/MediaKeys.idl

@@ -35,5 +35,5 @@
 
     [CallWith=ExecutionContext, RaisesException] MediaKeySession createSession(DOMString type, Uint8Array initData);
 
-    static boolean isTypeSupported(DOMString keySystem, [Default=NullString] optional DOMString contentType);
+    static boolean isTypeSupported(DOMString keySystem, optional DOMString contentType = null);
 };

third_party/WebKit/Source/modules/indexeddb/IDBDatabase.idl

@@ -36,9 +36,9 @@
     [RaisesException] IDBObjectStore createObjectStore(DOMString name, optional Dictionary options);
     [RaisesException] void deleteObjectStore(DOMString name);
     // FIXME: should be union type http://crbug.com/240176
-    [CallWith=ExecutionContext, RaisesException] IDBTransaction transaction(DOMString storeName, [Default=NullString] optional DOMString mode);
-    [CallWith=ExecutionContext, RaisesException] IDBTransaction transaction(sequence<DOMString> storeNames, [Default=NullString] optional DOMString mode);
-    [CallWith=ExecutionContext, RaisesException] IDBTransaction transaction(DOMStringList storeNames, [Default=NullString] optional DOMString mode);
+    [CallWith=ExecutionContext, RaisesException] IDBTransaction transaction(DOMString storeName, optional DOMString mode = null);
+    [CallWith=ExecutionContext, RaisesException] IDBTransaction transaction(sequence<DOMString> storeNames, optional DOMString mode = null);
+    [CallWith=ExecutionContext, RaisesException] IDBTransaction transaction(DOMStringList storeNames, optional DOMString mode = null);
     void close();
     attribute EventHandler onabort;
     attribute EventHandler onclose;

third_party/WebKit/Source/modules/indexeddb/IDBIndex.idl

@@ -32,8 +32,8 @@
     readonly attribute boolean unique;
     readonly attribute boolean multiEntry;
 
-    [CallWith=ScriptState, RaisesException] IDBRequest openCursor([Default=Undefined] optional any range, [Default=NullString] optional DOMString direction);
-    [CallWith=ScriptState, RaisesException] IDBRequest openKeyCursor([Default=Undefined] optional any range, [Default=NullString] optional DOMString direction);
+    [CallWith=ScriptState, RaisesException] IDBRequest openCursor([Default=Undefined] optional any range, optional DOMString direction = null);
+    [CallWith=ScriptState, RaisesException] IDBRequest openKeyCursor([Default=Undefined] optional any range, optional DOMString direction = null);
 
     [CallWith=ScriptState, RaisesException] IDBRequest get(any key);
     [CallWith=ScriptState, RaisesException] IDBRequest getKey(any key);

third_party/WebKit/Source/modules/indexeddb/IDBObjectStore.idl

@@ -39,8 +39,8 @@
     [CallWith=ScriptState, ImplementedAs=deleteFunction, RaisesException] IDBRequest delete(any key);
     [CallWith=ScriptState, RaisesException] IDBRequest get(any key);
     [CallWith=ScriptState, RaisesException] IDBRequest clear();
-    [CallWith=ScriptState, RaisesException] IDBRequest openCursor([Default=Undefined] optional any range, [Default=NullString] optional DOMString direction);
-    [CallWith=ScriptState, RaisesException, RuntimeEnabled=IndexedDBExperimental] IDBRequest openKeyCursor([Default=Undefined] optional any range, [Default=NullString] optional DOMString direction);
+    [CallWith=ScriptState, RaisesException] IDBRequest openCursor([Default=Undefined] optional any range, optional DOMString direction = null);
+    [CallWith=ScriptState, RaisesException, RuntimeEnabled=IndexedDBExperimental] IDBRequest openKeyCursor([Default=Undefined] optional any range, optional DOMString direction = null);
     // FIXME: should be union type http://crbug.com/240176
     [CallWith=ScriptState, RaisesException] IDBIndex createIndex(DOMString name, DOMString keyPath, optional Dictionary options);
     [CallWith=ScriptState, RaisesException] IDBIndex createIndex(DOMString name, sequence<DOMString> keyPath, optional Dictionary options);

third_party/WebKit/Source/modules/speech/SpeechSynthesisUtterance.idl

@@ -25,7 +25,7 @@
 
 [
     GarbageCollected,
-    Constructor([Default=NullString] optional DOMString text),
+    Constructor(optional DOMString text = null),
     ConstructorCallWith=ExecutionContext,
     RuntimeEnabled=SpeechSynthesis,
 ] interface SpeechSynthesisUtterance : EventTarget {