Fix build error.

src/regexp-macro-assembler-tracer.cc

Index: src/regexp-macro-assembler-tracer.cc
diff --git a/src/regexp-macro-assembler-tracer.cc b/src/regexp-macro-assembler-tracer.cc
index 0a638e73204f5e59e689fb276ae2628c478405bd..f8432784f2cd90166c29d79f5c1ba27509946768 100644
--- a/src/regexp-macro-assembler-tracer.cc
+++ b/src/regexp-macro-assembler-tracer.cc
@@ -38,7 +38,7 @@ RegExpMacroAssemblerTracer::RegExpMacroAssemblerTracer(
   assembler_(assembler) {
   unsigned int type = assembler->Implementation();
   ASSERT(type < 5);
-  const char* impl_names[4] = {"IA32", "ARM", "MIPS", "X64", "Bytecode"};
+  const char* impl_names[] = {"IA32", "ARM", "MIPS", "X64", "Bytecode"};
   PrintF("RegExpMacroAssembler%s();\n", impl_names[type]);
 }