Remove EventTarget, and subsequent fallout.

The primary goal of this change was to remove EventTarget from the
sky_engine C++ code. Since EventTarget is so core to the entire event
system that sky_engine was based on, this is a rather invasive change.
As such, it had some knock-on effects. I deleted some of the files
that were affected, and cauterised the remainder.

In many cases, a file would depend on another file that it didn't
include directly, but instead included indirectly via another file
that I deleted. When this happened, if the features that this broke
were obsolete, I sometimes just removed the features instead.

Specifically:
- removed EventTarget
- removed EventQueue, since without a target, what's a queue going to
  do?
- same with EventDispatch*
- removed ExecutionContext, since it had an EventQueue and nothing
  else it did was relevant to Sky anymore
- removed ActiveDOMObject, which was all about ExecutionContexts
- removed ContextLifecycleNotifier since it dependend on
  ExecutionContext and ActiveDOMObject
- removed the other Lifecycle classes for consistency, and replaced
  them with four booleans in the Document class
- removed some of the attributes that are no longer relevant from
  IDLExtendedAttributes (ConstructorCallWith and
  CallWith=ExecutionContext)
- removed the Document member on DOMDartState since we never set it to
  anything but null.
- removed BuiltinSky::InstallWindow since it relied on the Document
  member of DOMDartState
- removed EventHandler, EventListener, and mentions of those in
  various binding scripts
- removed NewEventHandler, since we're not using that either
- removed the following interfaces from the Sky Dart API:
  - EventTarget
  - EventListener (since without a target, there's no way to listen)
  - FocusEvent (since it's only member was an EventTarget)
  - HashChangeEvent (mostly by accident, but it's defunct anyway)
  - FontFace (it used ConstructorCallWith=ExecutionContext)
- changed the following interfaces of the Sky DART API:
  - MediaQueryList is no longer an EventTarget
  - Node is no longer an EventTarget
  - Document no longer has defaultView (depended on
    DOMDartState's document)
  - DocumentFragment, Element, Range, and Text no longer have a
    constructor (they all depended on DOMDartState's document, which
    is now gone)
  - Event lost its EventTarget members and path.
  - Window lost its WindowTimers partial interface (it used
    EventTarget and ExecutionContext a lot)
- removed numerous hacks in the bindings around features that are now
  gone, like addEventListener
- removed a bunch of console logging code, since that relied on
  ExecutionContext
- cauterised the wound in FontFace.cpp by removing constructors and
  methods that called now-removed features
- same with MediaQuery and friends
- same with some editor features and focus-related features
- same with Document
- removed DOMTimer classes since they use ExecutionContexts

Author: Hixie

sky/engine/bindings/BUILD.gn

@@ -13,11 +13,8 @@ source_set("bindings") {
     "builtin_natives.h",
     "builtin_sky.cc",
     "builtin_sky.h",
-    "custom/dart_element_custom.cc",
     "dart_callback.cc",
     "dart_callback.h",
-    "dart_event_listener.cc",
-    "dart_event_listener.h",
     "exception_messages.cc",
     "exception_messages.h",
     "exception_state.cc",

sky/engine/bindings/IDLExtendedAttributes.txt

@@ -35,11 +35,8 @@
 
 ActiveDOMObject
 CachedAttribute=*
-CallWith=ExecutionContext|ScriptState|ScriptArguments|ActiveWindow|FirstWindow|ThisValue
+CallWith=ScriptState|ScriptArguments|ActiveWindow|FirstWindow|ThisValue
 Constructor
-# FIXME: remove [ConstructorCallWith=Document], as can instead use
-# [ConstructorCallWith=ExecutionContext] + toDocument(executionContext)
-ConstructorCallWith=ExecutionContext|Document
 Custom=|Getter|Setter|VisitDOMWrapper|Wrap|PropertyGetter|PropertyEnumerator|PropertyQuery
 CustomConstructor
 CustomElementCallbacks

sky/engine/bindings/builtin_sky.cc

@@ -20,13 +20,6 @@ BuiltinSky::BuiltinSky(DOMDartState* dart_state) {
 BuiltinSky::~BuiltinSky() {
 }
 
-void BuiltinSky::InstallWindow(DOMDartState* dart_state) {
-  CHECK(!LogIfError(Dart_SetField(library_.value(),
-    ToDart("window"),
-    ToDart(dart_state->CurrentWindow()))));
-  // TODO(abarth): Retain the document wrapper.
-}
-
 void BuiltinSky::InstallView(View* view) {
   CHECK(!LogIfError(
       Dart_SetField(library_.value(), ToDart("view"), ToDart(view))));

sky/engine/bindings/builtin_sky.h

@@ -19,7 +19,6 @@ class BuiltinSky : public DartClassProvider {
   explicit BuiltinSky(DOMDartState* dart_state);
   ~BuiltinSky();
 
-  void InstallWindow(DOMDartState* dart_state);
   void InstallView(View* view);
 
   // DartClassProvider:

sky/engine/bindings/custom/dart_element_custom.cc

@@ -19,7 +19,7 @@ ScheduledAction::ScheduledAction(DartState* dart_state, Dart_Handle closure)
 ScheduledAction::~ScheduledAction() {
 }
 
-void ScheduledAction::Execute(ExecutionContext*) {
+void ScheduledAction::Execute() {
   if (!closure_.dart_state())
     return;
   DartIsolateScope scope(closure_.dart_state()->isolate());

sky/engine/bindings/dart_event_listener.cc

@@ -24,7 +24,7 @@ class ScheduledAction {
 
   ~ScheduledAction();
 
-  void Execute(ExecutionContext*);
+  void Execute();
 
  private:
   ScheduledAction(DartState* dart_state, Dart_Handle closure);

sky/engine/bindings/dart_event_listener.h

@@ -158,13 +158,6 @@ def cpp_argument(argument):
         if idl_type.name == 'MojoDataPipeConsumer':
             return '%s.Pass()' % argument_name
 
-        if idl_type.name == 'EventListener':
-            if (interface.name == 'EventTarget' and
-                method.name == 'removeEventListener'):
-                # FIXME: remove this special case by moving get() into
-                # EventTarget::removeEventListener
-                return '%s.get()' % argument_name
-            return argument.name
         if idl_type.is_callback_interface:
             return '%s.release()' % argument_name
         return argument_name
@@ -235,11 +228,8 @@ def dart_value_to_local_cpp_value(interface, has_type_checking_interface,
     idl_type = argument.idl_type
     name = argument.name
 
-    # FIXME: V8 has some special logic around the addEventListener and
-    # removeEventListener methods that should be added in somewhere.
-    # There is also some logic in systemnative.py to force a null check
-    # for the useCapture argument of those same methods that we may need to
-    # pull over.
+    # TODO(ianh): why don't we need to null-check everything?
+    # https://github.com/domokit/mojo/issues/280
     null_check = ((argument.is_optional and idl_type.is_callback_interface) or
                   (argument.default_value and argument.default_value.is_null))