tracing v2: Introduce TraceBufferReader to read-back the trace buffer

components/tracing/core/proto_utils.cc

 // Copyright 2016 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 "components/tracing/core/proto_utils.h"
 
 #include <limits>
 
 #include "base/sys_byteorder.h"
 
@@ skipping 56 matching lines @@
       *field_intvalue = base::ByteSwapToLE32(tmp);
       pos += sizeof(uint32_t);
       break;
     }
     case kFieldTypeVarInt: {
       pos = ParseVarInt(pos, end, field_intvalue);
       break;
     }
     case kFieldTypeLengthDelimited: {
       pos = ParseVarInt(pos, end, field_intvalue);
+      CHECK_LE(*field_intvalue, kMaxMessageLength);
       pos += *field_intvalue;
       CHECK_PTR_LE(pos, end);
       break;
     }
     default:
       NOTREACHED() << "Unsupported proto field type " << *field_type;
   }
   return pos;
 }
 
 }  // namespace proto
 }  // namespace v2
 }  // namespace tracing