[heap] Clean-up uses of EnsureSweepingComplete uses.

src/heap/mark-compact.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/heap/mark-compact.h"
 
 #include "src/base/atomicops.h"
 #include "src/base/bits.h"
 #include "src/base/sys-info.h"
 #include "src/code-stubs.h"
@@ skipping 758 matching lines @@
 void MarkCompactCollector::Prepare() {
   was_marked_incrementally_ = heap()->incremental_marking()->IsMarking();
 
 #ifdef DEBUG
   DCHECK(state_ == IDLE);
   state_ = PREPARE_GC;
 #endif
 
   DCHECK(!FLAG_never_compact || !FLAG_always_compact);
 
-  if (sweeping_in_progress()) {
-    // Instead of waiting we could also abort the sweeper threads here.
-    EnsureSweepingCompleted();
-  }
+  // Instead of waiting we could also abort the sweeper threads here.
+  EnsureSweepingCompleted();
 
   if (heap()->incremental_marking()->IsSweeping()) {
     heap()->incremental_marking()->Stop();
   }
 
   // If concurrent unmapping tasks are still running, we should wait for
   // them here.
   heap()->memory_allocator()->unmapper()->WaitUntilCompleted();
 
   // Clear marking bits if incremental marking is aborted.
@@ skipping 3288 matching lines @@
       // The target is always in old space, we don't have to record the slot in
       // the old-to-new remembered set.
       DCHECK(!heap()->InNewSpace(target));
       RecordRelocSlot(host, &rinfo, target);
     }
   }
 }
 
 }  // namespace internal
 }  // namespace v8