[Streams API] Implement a barebone ReadableStream interface

[Streams API] Implement a barebone ReadableStream interface
https://bugs.webkit.org/show_bug.cgi?id=141045

Reviewed by Benjamin Poulain.

.:

* Source/cmake/WebKitFeatures.cmake:
* Source/cmakeconfig.h.cmake: Made streams API compilation on by default.

Source/JavaScriptCore:

* Configurations/FeatureDefines.xcconfig:

Source/WebCore:

This patch implements the ReadableStream IDL (https://streams.spec.whatwg.org/#rs-model).
No functionality is yet added.
ReadableStreamSource is expected to be implemented for native sources (such as HTTP sources)
as well as JavaScript source through ReadableStreamJSSource.

Test: streams/readablestream-constructor.html

* CMakeLists.txt:
* Configurations/FeatureDefines.xcconfig:
* DerivedSources.cpp:
* DerivedSources.make:
* Modules/streams/ReadableStream.cpp: Added.
(WebCore::ReadableStream::create):
(WebCore::ReadableStream::ReadableStream):
(WebCore::ReadableStream::~ReadableStream):
(WebCore::ReadableStream::state):
(WebCore::ReadableStream::closed):
(WebCore::ReadableStream::ready):
* Modules/streams/ReadableStream.h: Added.
* Modules/streams/ReadableStream.idl: Added.
* Modules/streams/ReadableStreamSource.h: Added.
* WebCore.vcxproj/WebCore.vcxproj:
* WebCore.vcxproj/WebCore.vcxproj.filters:
* WebCore.vcxproj/WebCoreCommon.props:
* WebCore.xcodeproj/project.pbxproj:
* bindings/js/JSBindingsAllInOne.cpp:
* bindings/js/JSReadableStreamCustom.cpp: Added.
(WebCore::JSReadableStream::read):
(WebCore::JSReadableStream::ready):
(WebCore::JSReadableStream::closed):
(WebCore::JSReadableStream::cancel):
(WebCore::JSReadableStream::pipeTo):
(WebCore::JSReadableStream::pipeThrough):
(WebCore::constructJSReadableStream):
* bindings/js/ReadableStreamJSSource.cpp: Added.
(WebCore::ReadableStreamJSSource::create):
(WebCore::ReadableStreamJSSource::ReadableStreamJSSource):
(WebCore::ReadableStreamJSSource::setInternalError):
* bindings/JSReadableStreamJSSource.h: Added.

Source/WebKit/mac:

* Configurations/FeatureDefines.xcconfig:

Source/WebKit2:

* CMakeLists.txt:
* Configurations/FeatureDefines.xcconfig:

Source/WTF:

* wtf/FeatureDefines.h:

Tools:

* Scripts/webkitperl/FeatureList.pm: Added streams-api compilation switch.

LayoutTests:

Added readablestream-constructor test that checks ReadableStream properties and state.
Rebased global-constructor-attributes.html expectations to add ReadableStream description.

* js/dom/global-constructors-attributes-expected.txt:
* platform/efl/js/dom/global-constructors-attributes-expected.txt:
* platform/gtk/js/dom/global-constructors-attributes-expected.txt:
* platform/ios-sim-deprecated/js/dom/global-constructors-attributes-expected.txt:
* platform/mac-mavericks/js/dom/global-constructors-attributes-expected.txt:
* platform/mac-mountainlion/js/dom/global-constructors-attributes-expected.txt:
* platform/mac/js/dom/global-constructors-attributes-expected.txt:
* platform/win/js/dom/global-constructors-attributes-expected.txt:
* streams/readablestream-constructor-expected.txt: Added.
* streams/readablestream-constructor.html: Added.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@179687 268f45cc-cd09-0410-ab3c-d52691b4dbfc