https://bugs.webkit.org/show_bug.cgi?id=119335

Reviewed by Darin Adler.

Use emptyString() instead of String("") because it is better style and
faster. This is a followup to r116908, removing all occurrences of
String("") from WebKit.

Source/JavaScriptCore:

* runtime/RegExpConstructor.cpp:
(JSC::constructRegExp):
* runtime/RegExpPrototype.cpp:
(JSC::regExpProtoFuncCompile):
* runtime/StringPrototype.cpp:
(JSC::stringProtoFuncMatch):
(JSC::stringProtoFuncSearch):

Source/WebCore:

No behavior change, no new tests needed.

* platform/graphics/blackberry/LayerAnimation.h:
(WebCore::LayerAnimation::name):
* platform/mac/PlatformEventFactoryMac.mm:
(WebCore::textFromEvent):
(WebCore::unmodifiedTextFromEvent):
(WebCore::keyIdentifierForKeyEvent):

Source/WebKit/mac:

* WebCoreSupport/WebFrameLoaderClient.mm:
(WebFrameLoaderClient::userAgent):

Source/WebKit/qt:

* WebCoreSupport/ChromeClientQt.cpp:
(WebCore::ChromeClientQt::runJavaScriptPrompt):

Source/WebKit2:

* Shared/mac/WebEventFactory.mm:
(WebKit::textFromEvent):
(WebKit::unmodifiedTextFromEvent):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153546 268f45cc-cd09-0410-ab3c-d52691b4dbfc