[WebCrypto] Remove experimental feature flag of SubtleCrypto

[WebCrypto] Remove experimental feature flag of SubtleCrypto
https://bugs.webkit.org/show_bug.cgi?id=173197
<rdar://problem/32688148>

Reviewed by Brent Fulgham.

Source/WebCore:

The SubtleCrypto implementation is no longer experimental and is ready for production use. We are therefore removing the runtime flag.

No tests.

* page/Crypto.idl:
* page/RuntimeEnabledFeatures.h:
(WebCore::RuntimeEnabledFeatures::setSubtleCryptoEnabled): Deleted.
(WebCore::RuntimeEnabledFeatures::subtleCryptoEnabled): Deleted.

Source/WebKit/mac:

* WebView/WebPreferences.mm:
(+[WebPreferences initialize]):
(-[WebPreferences subtleCryptoEnabled]): Deleted.
(-[WebPreferences setSubtleCryptoEnabled:]): Deleted.
* WebView/WebPreferencesPrivate.h:
* WebView/WebView.mm:
(-[WebView _preferencesChanged:]):

Source/WebKit2:

* Shared/WebPreferencesDefinitions.h:
* UIProcess/API/C/WKPreferences.cpp:
(WKPreferencesSetSubtleCryptoEnabled): Deleted.
(WKPreferencesGetSubtleCryptoEnabled): Deleted.
* UIProcess/API/C/WKPreferencesRefPrivate.h:
* WebProcess/InjectedBundle/InjectedBundle.cpp:
(WebKit::InjectedBundle::overrideBoolPreferenceForTestRunner):
* WebProcess/WebPage/WebPage.cpp:
(WebKit::WebPage::updatePreferences):

Tools:

* DumpRenderTree/mac/DumpRenderTree.mm:
(enableExperimentalFeatures):
* WebKitTestRunner/InjectedBundle/InjectedBundle.cpp:
(WTR::InjectedBundle::beginTesting):
* WebKitTestRunner/InjectedBundle/TestRunner.cpp:
(WTR::TestRunner::setSubtleCryptoEnabled): Deleted.
* WebKitTestRunner/InjectedBundle/TestRunner.h:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@218129 268f45cc-cd09-0410-ab3c-d52691b4dbfc