VM: Const-correctness fixes.

runtime/vm/timeline.h

 // Copyright (c) 2015, 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_TIMELINE_H_
 #define VM_TIMELINE_H_
 
 #include "vm/allocation.h"
 #include "vm/bitfield.h"
 #include "vm/os.h"
@@ skipping 312 matching lines @@
 
 #define TIMELINE_FUNCTION_COMPILATION_DURATION(thread, suffix, function)       \
   TimelineDurationScope tds(thread,                                            \
                             thread->isolate()->GetCompilerStream(),            \
                             "Compile" suffix);                                 \
   if (tds.enabled()) {                                                         \
     tds.SetNumArguments(1);                                                    \
     tds.CopyArgument(                                                          \
         0,                                                                     \
         "function",                                                            \
-        const_cast<char*>(function.ToLibNamePrefixedQualifiedCString()));      \
+        function.ToLibNamePrefixedQualifiedCString());                         \
   }
 
 
 // See |TimelineDurationScope| and |TimelineBeginEndScope|.
 class TimelineEventScope : public StackResource {
  public:
   bool enabled() const {
     return enabled_;
   }
 
@@ skipping 361 matching lines @@
 
  private:
   TimelineEventBlock* current_;
   TimelineEventRecorder* recorder_;
 };
 
 
 }  // namespace dart
 
 #endif  // VM_TIMELINE_H_