[wasm] Use a Managed<WasmModule> to hold metadata about modules.

src/signature.h

 // Copyright 2015 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_SIGNATURE_H_
 #define V8_SIGNATURE_H_
 
 #include "src/zone/zone.h"
 
 namespace v8 {
@@ skipping 14 matching lines @@
   T GetParam(size_t index) const {
     DCHECK(index < parameter_count_);
     return reps_[return_count_ + index];
   }
 
   T GetReturn(size_t index = 0) const {
     DCHECK(index < return_count_);
     return reps_[index];
   }
 
-  const T* raw_data() const { return reps_; }
-
   // For incrementally building signatures.
   class Builder {
    public:
     Builder(Zone* zone, size_t return_count, size_t parameter_count)
         : return_count_(return_count),
           parameter_count_(parameter_count),
           zone_(zone),
           rcursor_(0),
           pcursor_(0),
           buffer_(zone->NewArray<T>(
@@ skipping 26 matching lines @@
  protected:
   size_t return_count_;
   size_t parameter_count_;
   const T* reps_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_SIGNATURE_H_