Correctly compute line numbers in functions from the function constructor.

src/messages.js

Index: src/messages.js
diff --git a/src/messages.js b/src/messages.js
index cba474538eda764a926818345812af0077c74459..6687b5215163cd1b18761d7947cd6ff4ef3233a3 100644
--- a/src/messages.js
+++ b/src/messages.js
@@ -392,34 +392,26 @@ function MakeReferenceErrorEmbedded(type, arg) {
        else the line number.
  */
 function ScriptLineFromPosition(position) {
-  var lower = 0;
-  var upper = this.lineCount() - 1;
   var line_ends = this.line_ends;
+  var upper = line_ends.length - 1;
+  if (upper < 0) return -1;
 
   // We'll never find invalid positions so bail right away.
-  if (position > line_ends[upper]) {
-    return -1;
-  }
-
-  // This means we don't have to safe-guard indexing line_ends[i - 1].
-  if (position <= line_ends[0]) {
-    return 0;
-  }
-
-  // Binary search to find line # from position range.
-  while (upper >= 1) {
-    var i = (lower + upper) >> 1;
-
-    if (position > line_ends[i]) {
-      lower = i + 1;
-    } else if (position <= line_ends[i - 1]) {
-      upper = i - 1;
+  if (position > line_ends[upper]) return -1;
+  if (position <= line_ends[0]) return 0;
+
+  var lower = 1;
+  // Binary search.
+  while (true) {
+    var mid = (upper + lower) >> 1;
+    if (position <= line_ends[mid - 1]) {
+      upper = mid - 1;
+    } else if (position > line_ends[mid]){
+      lower = mid + 1;
     } else {
-      return i;
+      return mid;
     }
   }
-
-  return -1;
 }
 
 /**