[oilpan]: Don't sweep while in safepoint.

Source/platform/heap/ThreadState.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 180 matching lines @@
         ASSERT(!state->isSweepInProgress());
         if (!acquireLoad(&m_canResume)) {
             // If we are leaving the safepoint from a SafePointAwareMutexLocker
             // call out to release the lock before going to sleep. This enables the
             // lock to be acquired in the sweep phase, e.g. during weak processing
             // or finalization. The SafePointAwareLocker will reenter the safepoint
             // and reacquire the lock after leaving this safepoint.
             if (locker)
                 locker->reset();
             pushAllRegisters(this, state, parkAfterPushRegisters);
-            state->performPendingSweep();
         }
     }
 
     void enterSafePoint(ThreadState* state)
     {
         ASSERT(!state->isSweepInProgress());
         pushAllRegisters(this, state, enterSafePointAfterPushRegisters);
     }
 
     void leaveSafePoint(ThreadState* state, SafePointAwareMutexLocker* locker = 0)
@@ skipping 539 matching lines @@
 void ThreadState::safePoint(StackState stackState)
 {
     checkThread();
     performPendingGC(stackState);
     ASSERT(!m_atSafePoint);
     m_stackState = stackState;
     m_atSafePoint = true;
     s_safePointBarrier->checkAndPark(this);
     m_atSafePoint = false;
     m_stackState = HeapPointersOnStack;
+    performPendingSweep();
 }
 
 #ifdef ADDRESS_SANITIZER
 // When we are running under AddressSanitizer with detect_stack_use_after_return=1
 // then stack marker obtained from SafePointScope will point into a fake stack.
 // Detect this case by checking if it falls in between current stack frame
 // and stack start and use an arbitrary high enough value for it.
 // Don't adjust stack marker in any other case to match behavior of code running
 // without AddressSanitizer.
 NO_SANITIZE_ADDRESS static void* adjustScopeMarkerForAdressSanitizer(void* scopeMarker)
@@ skipping 144 matching lines @@
                 threadAttachMutex().unlock();
             return gcInfo;
         }
     }
     if (needLockForIteration)
         threadAttachMutex().unlock();
     return 0;
 }
 #endif
 }