Restrict floating control to minimal control-connected component.

src/zone-allocator.h

 // Copyright 2014 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.
 
 #ifndef V8_ZONE_ALLOCATOR_H_
 #define V8_ZONE_ALLOCATOR_H_
 
 #include <limits>
 
 #include "src/zone.h"
@@ skipping 32 matching lines @@
   void deallocate(pointer p, size_type) { /* noop for Zones */ }
 
   size_type max_size() const throw() {
     return std::numeric_limits<int>::max() / sizeof(value_type);
   }
   void construct(pointer p, const T& val) {
     new(static_cast<void*>(p)) T(val);
   }
   void destroy(pointer p) { p->~T(); }
 
-  bool operator==(zone_allocator const& other) {
+  bool operator==(zone_allocator const& other) const {
     return zone_ == other.zone_;
   }
-  bool operator!=(zone_allocator const& other) {
+  bool operator!=(zone_allocator const& other) const {
     return zone_ != other.zone_;
   }
 
  private:
   zone_allocator();
   Zone* zone_;
 };
 
 typedef zone_allocator<bool> ZoneBoolAllocator;
 typedef zone_allocator<int> ZoneIntAllocator;
 } }  // namespace v8::internal
 
 #endif  // V8_ZONE_ALLOCATOR_H_