Revert of improve perf_basic_prof filename reporting

src/log.cc

Index: src/log.cc
diff --git a/src/log.cc b/src/log.cc
index ea69fb4bee3e71cecb6ae6a38f8dba69445b3657..b9eb577b2054f5c5e84d7b02f91425ff06522f65 100644
--- a/src/log.cc
+++ b/src/log.cc
@@ -123,9 +123,8 @@
   }
 
   void AppendInt(int n) {
-    int space = kUtf8BufferSize - utf8_pos_;
-    if (space <= 0) return;
-    Vector<char> buffer(utf8_buffer_ + utf8_pos_, space);
+    Vector<char> buffer(utf8_buffer_ + utf8_pos_,
+                        kUtf8BufferSize - utf8_pos_);
     int size = SNPrintF(buffer, "%d", n);
     if (size > 0 && utf8_pos_ + size <= kUtf8BufferSize) {
       utf8_pos_ += size;
@@ -133,9 +132,8 @@
   }
 
   void AppendHex(uint32_t n) {
-    int space = kUtf8BufferSize - utf8_pos_;
-    if (space <= 0) return;
-    Vector<char> buffer(utf8_buffer_ + utf8_pos_, space);
+    Vector<char> buffer(utf8_buffer_ + utf8_pos_,
+                        kUtf8BufferSize - utf8_pos_);
     int size = SNPrintF(buffer, "%x", n);
     if (size > 0 && utf8_pos_ + size <= kUtf8BufferSize) {
       utf8_pos_ += size;
@@ -147,7 +145,7 @@
 
  private:
   static const int kUtf8BufferSize = 512;
-  static const int kUtf16BufferSize = kUtf8BufferSize;
+  static const int kUtf16BufferSize = 128;
 
   int utf8_pos_;
   char utf8_buffer_[kUtf8BufferSize];