https://bugs.webkit.org/show_bug.cgi?id=93773

Reviewed by Dan Bernstein.

Source/WebKit2: 

Use the XPC Service for WebProcess code path if WEBKIT_USE_XPC_SERVICE_FOR_WEB_PROCESS
is set in the environment.

* UIProcess/Launcher/mac/ProcessLauncherMac.mm:
(WebKit::launchXPCService):
Fix issue that was causing this code not to compile. This was not caught before since
the code was not being built.
        
* UIProcess/WebProcessProxy.cpp:
(WebKit::WebProcessProxy::connect):
Switch from hard coding always using the XPC Service code path if
HAVE(XPC) was true, to doing it conditionally on an environment variable.

Source/WTF: 

* wtf/Platform.h:
Define HAVE_XPC on 10.7 and later.

Tools: 

Convert --use-web-process-xpc-service passed to run-safari (and similar scripts)
to setting WEBKIT_USE_XPC_SERVICE_FOR_WEB_PROCESS=YES in the environment and setting
up __XPC_DYLD_FRAMEWORK_PATH and __XPC_DYLD_INSERT_LIBRARIES variables. NOTE: using
the XPC service is not the default code path.

* Scripts/webkitdirs.pm:
(shouldUseXPCServiceForWebProcess):
(determineShouldUseXPCServiceForWebProcess):
Add functions to extract --use-web-process-xpc-service from ARGV and set a
global variable.

(printHelpAndExitForRunAndDebugWebKitAppIfNeeded):
Add help text for --use-web-process-xpc-service.

(runMacWebKitApp):
Set the WEBKIT_USE_XPC_SERVICE_FOR_WEB_PROCESS environment variable and DYLD
if --use-web-process-xpc-service was passed on the command line.

(execMacWebKitAppForDebugging):
Set the WEBKIT_USE_XPC_SERVICE_FOR_WEB_PROCESS environment variable and DYLD
if --use-web-process-xpc-service was passed on the command line. Also, bail
if both --use-web-process-xpc-service and --target-web-process are passed on
the command line, as we don't currently support using both.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@125361 268f45cc-cd09-0410-ab3c-d52691b4dbfc