Another round of MSVC fixes.

src/hydrogen-gvn.h

 // Copyright 2013 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_HYDROGEN_GVN_H_
 #define V8_HYDROGEN_GVN_H_
 
 #include "src/compiler.h"
 #include "src/hydrogen.h"
 #include "src/hydrogen-instructions.h"
@@ skipping 37 matching lines @@
     ASSERT(special >= 0);
     ASSERT(special < kNumberOfSpecials);
     return static_cast<uint64_t>(1) << static_cast<unsigned>(
         special + kNumberOfFlags);
   }
 
   uint64_t bits_;
 };
 
 
-class TrackedEffects;
+struct TrackedEffects;
 
 // Tracks global variable and inobject field loads/stores in a fine grained
 // fashion, and represents them using the "special" dynamic side effects of the
 // SideEffects class (see above). This way unrelated global variable/inobject
 // field stores don't prevent hoisting and merging of global variable/inobject
 // field loads.
 class SideEffectsTracker V8_FINAL BASE_EMBEDDED {
  public:
   SideEffectsTracker() : num_global_vars_(0), num_inobject_fields_(0) {}
   SideEffects ComputeChanges(HInstruction* instr);
@@ skipping 75 matching lines @@
   // Used when collecting side effects on paths from dominator to
   // dominated.
   BitVector visited_on_paths_;
 
   DISALLOW_COPY_AND_ASSIGN(HGlobalValueNumberingPhase);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_GVN_H_