Oilpan: Scale up the number of marking threads according to available processors

Source/platform/heap/Heap.cpp

Index: Source/platform/heap/Heap.cpp
diff --git a/Source/platform/heap/Heap.cpp b/Source/platform/heap/Heap.cpp
index fb73381446f1fa96c9e0ffac812c603b15e9e05c..fe91e41e8de11f975323192664639643827fc205 100644
--- a/Source/platform/heap/Heap.cpp
+++ b/Source/platform/heap/Heap.cpp
@@ -2141,11 +2141,10 @@ void Heap::init()
     s_orphanedPagePool = new OrphanedPagePool();
     s_markingThreads = new Vector<OwnPtr<blink::WebThread> >();
     if (blink::Platform::current()) {
-        // FIXME: We should let the amount of threads scale with the
-        // amount of processors in the system instead of hardcoding
-        // it.
+        int processors = blink::Platform::current()->numberOfProcessors();
+        int numberOfMarkingThreads = std::min(processors, maxNumberOfMarkingThreads);
         for (int i = 0; i < numberOfMarkingThreads; i++)
-            s_markingThreads->append(adoptPtr(blink::Platform::current()->createThread("Blink Heap Marker Thread")));
+            s_markingThreads->append(adoptPtr(blink::Platform::current()->createThread("Blink GC Marking Thread")));
     }
 }