8068037: Remove dead code in G1CollectedHeap

Reviewed-by: stefank, tschatzl

hotspot/src/share/vm/gc_implementation/g1/concurrentMark.cpp

@@ -1910,7 +1910,6 @@ public:
   }
 
   void work(uint worker_id) {
-    double start = os::elapsedTime();
     FreeRegionList local_cleanup_list("Local Cleanup List");
     HRRSCleanupTask hrrs_cleanup_task;
     G1NoteEndOfConcMarkClosure g1_note_end(_g1h, &local_cleanup_list,

hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp

@@ -1229,7 +1229,6 @@ bool G1CollectedHeap::do_collection(bool explicit_gc,
       TraceCollectorStats tcs(g1mm()->full_collection_counters());
       TraceMemoryManagerStats tms(true /* fullGC */, gc_cause());
 
-      double start = os::elapsedTime();
       g1_policy()->record_full_collection_start();
 
       // Note: When we have a more flexible GC logging framework that
@@ -1436,7 +1435,6 @@ bool G1CollectedHeap::do_collection(bool explicit_gc,
 
       _allocator->init_mutator_alloc_region();
 
-      double end = os::elapsedTime();
       g1_policy()->record_full_collection_end();
 
       if (G1Log::fine()) {

hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp

@@ -56,7 +56,6 @@ class HRRSCleanupTask;
 class GenerationSpec;
 class OopsInHeapRegionClosure;
 class G1KlassScanClosure;
-class G1ScanHeapEvacClosure;
 class ObjectClosure;
 class SpaceClosure;
 class CompactibleSpaceClosure;

hotspot/src/share/vm/gc_implementation/g1/g1MarkSweep.hpp

@@ -46,9 +46,6 @@ class ReferenceProcessor;
 class G1PrepareCompactClosure;
 
 class G1MarkSweep : AllStatic {
-  friend class VM_G1MarkSweep;
-  friend class Scavenge;
-
  public:
 
   static void invoke_at_safepoint(ReferenceProcessor* rp,

hotspot/src/share/vm/gc_implementation/g1/g1RemSet.hpp

@@ -31,7 +31,6 @@
 // collection set.
 
 class G1CollectedHeap;
-class CardTableModRefBarrierSet;
 class ConcurrentG1Refine;
 class G1ParPushHeapRSClosure;