Coverity: Fully initialize the |trace_| member variable.

base/debug/stack_trace.cc

 // Copyright (c) 2011 The Chromium 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 "base/debug/stack_trace.h"
 
 #include "base/basictypes.h"
 
 #include <string.h>
 
 #include <algorithm>
 #include <sstream>
 
 namespace base {
 namespace debug {
 
 StackTrace::StackTrace(const void* const* trace, size_t count) {
   count = std::min(count, arraysize(trace_));
   if (count)
     memcpy(trace_, trace, count * sizeof(trace_[0]));
-  count_ = static_cast<int>(count);
+  count_ = count;
 }
 
 StackTrace::~StackTrace() {
 }
 
 const void *const *StackTrace::Addresses(size_t* count) const {
   *count = count_;
   if (count_)
     return trace_;
   return NULL;
 }
 
 std::string StackTrace::ToString() const {
   std::stringstream stream;
   OutputToStream(&stream);
   return stream.str();
 }
 
 }  // namespace debug
 }  // namespace base