Fix Linux build: (unnecessarily) initialize record so that warnings are shut down.

runtime/vm/raw_object.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_RAW_OBJECT_H_
 #define VM_RAW_OBJECT_H_
 
 #include "platform/assert.h"
 #include "vm/globals.h"
 #include "vm/token.h"
@@ skipping 899 matching lines @@
     kOptStaticCall   = kIcCall << 1,  // Call directly to known target.
     kUnoptStaticCall = kOptStaticCall << 1,  // Call to a known target via stub.
     kClosureCall     = kUnoptStaticCall << 1,  // Closure call.
     kRuntimeCall     = kClosureCall << 1,  // Runtime call.
     kOsrEntry        = kRuntimeCall << 1,  // OSR entry point in unopt. code.
     kOther           = kOsrEntry << 1,
     kAnyKind         = 0xFF
   };
 
   // Compressed version assumes try_index is always -1 and does not store it.
-  struct PcDescriptorRec {
+  class PcDescriptorRec {
+   public:
+    PcDescriptorRec()
+        : pc_(0), deopt_id_and_kind_(0), token_pos_(0), try_index_(0) {}
+
     uword pc() const { return pc_; }
     void set_pc(uword value) { pc_ = value; }
 
     Kind kind() const {
       return static_cast<Kind>(deopt_id_and_kind_ & kAnyKind);
     }
     void set_kind(Kind kind) {
       deopt_id_and_kind_ = (deopt_id_and_kind_ & 0xFFFFFF00) | kind;
     }
 
@@ skipping 1015 matching lines @@
   COMPILE_ASSERT(kTypedDataInt8ArrayViewCid == kTypedDataInt8ArrayCid + 14);
   COMPILE_ASSERT(kExternalTypedDataInt8ArrayCid ==
                  kTypedDataInt8ArrayViewCid + 15);
   COMPILE_ASSERT(kNullCid == kExternalTypedDataInt8ArrayCid + 14);
   return (kNullCid - kTypedDataInt8ArrayCid);
 }
 
 }  // namespace dart
 
 #endif  // VM_RAW_OBJECT_H_