Remove support for logging into a memory buffer.

src/log.h

Index: src/log.h
diff --git a/src/log.h b/src/log.h
index 6ffd18c61bedea97133e73c6067c1df2ecec507d..9a36badaf010272c73d037079663922b0c8500c4 100644
--- a/src/log.h
+++ b/src/log.h
@@ -284,10 +284,6 @@ class Logger {
   void ResumeProfiler();
   bool IsProfilerPaused();
 
-  // If logging is performed into a memory buffer, allows to
-  // retrieve previously written messages. See v8.h.
-  int GetLogLines(int from_pos, char* dest_buf, int max_size);
-
   // Logs all compiled functions found in the heap.
   void LogCompiledFunctions();
   // Logs all accessor callbacks found in the heap.