HTMLConstructor implementation

third_party/WebKit/Source/bindings/IDLExtendedAttributes.md

 # Blink IDL Extended Attributes
 
 [TOC]
 
 ## Introduction
 
 The main interest in extended attributes are their _semantics_: Blink implements many more extended attributes than the Web IDL standard, to specify various behavior.
 
 The authoritative list of allowed extended attributes and values is [bindings/IDLExtendedAttributes.txt](https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit/Source/bindings/IDLExtendedAttributes.txt). This is complete but not necessarily precise (there may be unused extended attributes or values), since validation is run on build, but coverage isn't checked.
 
@@ skipping 230 matching lines @@
 interface GraphicsContext {
     void setColor(octet red, octet green, octet blue);
     void setColorEnforced([EnforceRange] octet red, [EnforceRange] octet green, [EnforceRange] octet blue);
 };
 ```
 
 Calling the non-`[EnforceRange]` version of `setColor()` uses **ToUint8()** to coerce the Numbers to octets. Hence calling `context.setColor(-1, 255, 257)` is equivalent to calling `setColor(255, 255, 1)`.
 
 Calling the `[EnforceRange]` version of `setColorEnforced()` with an out of range value, such as -1, 256, or Infinity will result in a `TypeError` exception.
 
+### [Exposed] _(i, m, a, c)_
+
+Standard: [Exposed](http://heycam.github.io/webidl/#Exposed)
+
+Summary: Indicates on which global object or objects (e.g., Window, WorkerGlobalScope) the interface property is generated, i.e., in which global scope or scopes an interface exists. This is primarily of interest for the constructor, i.e., the [interface object Call method](https://heycam.github.io/webidl/#es-interface-call). Global context defaults to Window (the primary global scope) if not present, overridden by standard extended attribute `[NoInterfaceObject]` (the value of the property on the global object corresponding to the interface is called the **interface object**), which results in no interface property being generated.
+
+As with `[NoInterfaceObject]` does not affect generated code for the interface itself, only the code for the corresponding global object. A partial interface is generated at build time, containing an attribute for each interface property on that global object.
+
+All non-callback interfaces without `[NoInterfaceObject]` have a corresponding interface property on the global object. Note that in the Web IDL spec, callback interfaces with constants also have interface properties, but in Blink callback interfaces only have methods (no constants or attributes), so this is not applicable. `[Exposed]` can be used with different values to indicate on which global object or objects the property should be generated. Valid values are:
+
+* `Window`
+* [Worker](http://www.whatwg.org/specs/web-apps/current-work/multipage/workers.html#the-workerglobalscope-common-interface)
+* [SharedWorker](http://www.whatwg.org/specs/web-apps/current-work/multipage/workers.html#dedicated-workers-and-the-dedicatedworkerglobalscope-interface)
+* [DedicatedWorker](http://www.whatwg.org/specs/web-apps/current-work/multipage/workers.html#shared-workers-and-the-sharedworkerglobalscope-interface)
+* [ServiceWorker](https://rawgithub.com/slightlyoff/ServiceWorker/master/spec/service_worker/index.html#service-worker-global-scope)
+
+For reference, see [ECMAScript 5.1: 15.1 The Global Object](http://www.ecma-international.org/ecma-262/5.1/#sec-15.1) ([annotated](http://es5.github.io/#x15.1)), [HTML: 10 Web workers](http://www.whatwg.org/specs/web-apps/current-work/multipage/workers.html), [Web Workers](http://dev.w3.org/html5/workers/), and [Service Workers](https://rawgithub.com/slightlyoff/ServiceWorker/master/spec/service_worker/index.html) specs.
+
+It is possible to have the global constructor generated on several interfaces by listing them, e.g. `[Exposed=(Window,WorkerGlobalScope)]`.
+
+Usage: `[Exposed]` can be specified on interfaces that do not have the `[NoInterfaceObject]` extended attribute.
+
+```webidl
+[
+    Exposed=DedicatedWorker,
+] interface XXX {
+    ...
+};
+
+[
+    Exposed=(Window,Worker),
+] interface YYY {
+    ...
+};
+```
+
+Exposed can also be specified with a method, attribute and constant.
+
+As a Blink-specific extension, we allow `Exposed(Arguments)` form, such as `[Exposed(Window Feature1, DedicatedWorker Feature2)]`. You can use this form to vary the exposing global scope based on runtime enabled features. For example, `[Exposed(Window Feature1, Worker Feature2)]` exposes the qualified element to Window if "Feature1" is enabled and to Worker if "Feature2" is enabled.
+
+### [Global] and [PrimaryGlobal] _(i)_
+
+Standard: [Global](http://heycam.github.io/webidl/#Global)
+
+Summary: The `[Global]` and `[PrimaryGlobal]` extended attributes can be used to give a name to one or more global interfaces, which can then be referenced by the `[Exposed]` extended attribute.
+
+These extended attributes must either take no arguments or take an identifier list.
+
+If the `[Global]` or `[PrimaryGlobal]` extended attribute is declared with an identifier list argument, then those identifiers are the interface’s global names; otherwise, the interface has a single global name, which is the interface's identifier.
+
+### [HTMLConstructor]
+
+Standard: [HTMLConstructor](https://html.spec.whatwg.org/multipage/dom.html#html-element-constructors)
+
+Summary: HTML Elements have special constructor behavior. Interface object of given interface with the `[HTMLConstructor]` attribute will have specific behavior when called.
+
+Usage: Must take no arguments, and must not appear on anything other than an interface. It much appear once on an interface, and the interface cannot be annotated with `[Constructor]` or `[NoInterfaceObject]` extended attributes. It must not be used on a callback interface.
 
 ### [NamedConstructor] _(i)_
 
 Standard: [NamedConstructor](https://heycam.github.io/webidl/#NamedConstructor)
 
 Summary: If you want to allow JavaScript to create a DOM object of XXX using a different name constructor (i.e. allow JavaScript to create an XXX object using "new YYY()", where YYY != XXX), you can use `[NamedConstructor]`.
 
 Usage: The possible usage is `[NamedConstructor=YYY(...)]`. Just as with constructors, an empty argument list can be omitted, as: `[NamedConstructor=YYY]`. `[NamedConstructor]` can be specified on interfaces. The spec allows multiple named constructors, but the Blink IDL compiler currently only supports at most one.
 
 ```webidl
@@ skipping 40 matching lines @@
 Note that `[NoInterfaceObject]` **MUST** be specified on testing interfaces, as follows:
 
 ```webidl
 [
     NoInterfaceObject, // testing interfaces do not appear on global objects
 ] interface TestingInterfaceX {
     ...
 };
 ```
 
-### [Global] and [PrimaryGlobal] _(i)_
-
-Standard: [Global](http://heycam.github.io/webidl/#Global)
-
-Summary: The `[Global]` and `[PrimaryGlobal]` extended attributes can be used to give a name to one or more global interfaces, which can then be referenced by the `[Exposed]` extended attribute.
-
-These extended attributes must either take no arguments or take an identifier list.
-
-If the `[Global]` or `[PrimaryGlobal]` extended attribute is declared with an identifier list argument, then those identifiers are the interface’s global names; otherwise, the interface has a single global name, which is the interface's identifier.
-
-### [Exposed] _(i, m, a, c)_
-
-Standard: [Exposed](http://heycam.github.io/webidl/#Exposed)
-
-Summary: Indicates on which global object or objects (e.g., Window, WorkerGlobalScope) the interface property is generated, i.e., in which global scope or scopes an interface exists. This is primarily of interest for the constructor, i.e., the [interface object Call method](https://heycam.github.io/webidl/#es-interface-call). Global context defaults to Window (the primary global scope) if not present, overridden by standard extended attribute `[NoInterfaceObject]` (the value of the property on the global object corresponding to the interface is called the **interface object**), which results in no interface property being generated.
-
-As with `[NoInterfaceObject]` does not affect generated code for the interface itself, only the code for the corresponding global object. A partial interface is generated at build time, containing an attribute for each interface property on that global object.
-
-All non-callback interfaces without `[NoInterfaceObject]` have a corresponding interface property on the global object. Note that in the Web IDL spec, callback interfaces with constants also have interface properties, but in Blink callback interfaces only have methods (no constants or attributes), so this is not applicable. `[Exposed]` can be used with different values to indicate on which global object or objects the property should be generated. Valid values are:
-
-* `Window`
-* [Worker](http://www.whatwg.org/specs/web-apps/current-work/multipage/workers.html#the-workerglobalscope-common-interface)
-* [SharedWorker](http://www.whatwg.org/specs/web-apps/current-work/multipage/workers.html#dedicated-workers-and-the-dedicatedworkerglobalscope-interface)
-* [DedicatedWorker](http://www.whatwg.org/specs/web-apps/current-work/multipage/workers.html#shared-workers-and-the-sharedworkerglobalscope-interface)
-* [ServiceWorker](https://rawgithub.com/slightlyoff/ServiceWorker/master/spec/service_worker/index.html#service-worker-global-scope)
-
-For reference, see [ECMAScript 5.1: 15.1 The Global Object](http://www.ecma-international.org/ecma-262/5.1/#sec-15.1) ([annotated](http://es5.github.io/#x15.1)), [HTML: 10 Web workers](http://www.whatwg.org/specs/web-apps/current-work/multipage/workers.html), [Web Workers](http://dev.w3.org/html5/workers/), and [Service Workers](https://rawgithub.com/slightlyoff/ServiceWorker/master/spec/service_worker/index.html) specs.
-
-It is possible to have the global constructor generated on several interfaces by listing them, e.g. `[Exposed=(Window,WorkerGlobalScope)]`.
-
-Usage: `[Exposed]` can be specified on interfaces that do not have the `[NoInterfaceObject]` extended attribute.
-
-```webidl
-[
-    Exposed=DedicatedWorker,
-] interface XXX {
-    ...
-};
-
-[
-    Exposed=(Window,Worker),
-] interface YYY {
-    ...
-};
-```
-
-Exposed can also be specified with a method, attribute and constant.
-
-As a Blink-specific extension, we allow `Exposed(Arguments)` form, such as `[Exposed(Window Feature1, DedicatedWorker Feature2)]`. You can use this form to vary the exposing global scope based on runtime enabled features. For example, `[Exposed(Window Feature1, Worker Feature2)]` exposes the qualified element to Window if "Feature1" is enabled and to Worker if "Feature2" is enabled.
-
 ### [OverrideBuiltins] _(i)_
 
 Standard: [OverrideBuiltins](http://heycam.github.io/webidl/#OverrideBuiltins)
 
 Summary: Affects named property operations, making named properties shadow built-in properties of the object.
 
 ### [PutForwards] _(a)_
 
 Standard: [PutForwards](http://heycam.github.io/webidl/#PutForwards)
 
@@ skipping 1218 matching lines @@
 Copyright (C) 2009 Apple Inc. All rights reserved.
 
 Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
 
 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
 
 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
 
 THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS “AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 ***