Move SourcePosition into separate header file.

src/assembler.h

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // All Rights Reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 // - Redistributions of source code must retain the above copyright notice,
 // this list of conditions and the following disclaimer.
 //
@@ skipping 31 matching lines @@
 #include "src/runtime/runtime.h"
 
 namespace v8 {
 
 // Forward declarations.
 class ApiFunction;
 
 namespace internal {
 
 // Forward declarations.
-class SourcePosition;
 class StatsCounter;
 
 // -----------------------------------------------------------------------------
 // Platform independent assembler base class.
 
 enum class CodeObjectRequired { kNo, kYes };
 
 
 class AssemblerBase: public Malloced {
  public:
@@ skipping 1215 matching lines @@
     std::vector<ConstantPoolEntry> shared_entries;
   };
 
   Label emitted_label_;  // Records pc_offset of emitted pool
   PerTypeEntryInfo info_[ConstantPoolEntry::NUMBER_OF_TYPES];
 };
 
 }  // namespace internal
 }  // namespace v8
 #endif  // V8_ASSEMBLER_H_