https://bugs.webkit.org/show_bug.cgi?id=56283
        
Reviewed by Sam Weinig.

ConservativeSet => ConservativeRoots. "Set" was misleading, since items
are not uniqued. Also, "Roots" is more specific about what's in the set.
        
MachineStackMarker => MachineThreads. "Threads" is more descriptive of
the fact that this class maintains a set of all threads using JSC.
"Stack" was misleading, since this class traverses stacks and registers.
"Mark" was misleading, since this class doesn't mark anything anymore.
        
registerThread => addCurrentThread. "Current" is more specific.
unregisterThread => removeCurrentThread. "Current" is more specific.
        
"currentThreadRegistrar" => threadSpecific. The only point of this data
structure is to register a thread-specific destructor with a pointer to
this.
        
"mark...Conservatively" => "gather". "Mark" is not true, since these
functions don't mark anything. "Conservatively" is redundant, since they
take "ConservativeRoots" as an argument.

* API/APIShims.h:
(JSC::APIEntryShimWithoutLock::APIEntryShimWithoutLock):
* JavaScriptCore.exp:
* runtime/ConservativeSet.cpp:
(JSC::ConservativeRoots::grow):
(JSC::ConservativeRoots::add):
* runtime/ConservativeSet.h:
(JSC::ConservativeRoots::ConservativeRoots):
(JSC::ConservativeRoots::~ConservativeRoots):
(JSC::ConservativeRoots::size):
(JSC::ConservativeRoots::roots):
* runtime/Heap.cpp:
(JSC::Heap::Heap):
(JSC::Heap::markRoots):
* runtime/Heap.h:
(JSC::Heap::machineThreads):
* runtime/JSGlobalData.h:
(JSC::JSGlobalData::makeUsableFromMultipleThreads):
* runtime/MachineStackMarker.cpp:
(JSC::MachineThreads::MachineThreads):
(JSC::MachineThreads::~MachineThreads):
(JSC::MachineThreads::makeUsableFromMultipleThreads):
(JSC::MachineThreads::addCurrentThread):
(JSC::MachineThreads::removeThread):
(JSC::MachineThreads::removeCurrentThread):
(JSC::MachineThreads::gatherFromCurrentThreadInternal):
(JSC::MachineThreads::gatherFromCurrentThread):
(JSC::MachineThreads::gatherFromOtherThread):
(JSC::MachineThreads::gatherConservativeRoots):
* runtime/MachineStackMarker.h:
* runtime/MarkStack.h:
(JSC::MarkStack::append):



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@80995 268f45cc-cd09-0410-ab3c-d52691b4dbfc