[type feedback] Allow position 0.

In eval scripts, the source code position can be 0 rather
than greater than 0.

Add regression test.

Drive-by fix: unrelated typo.

Bug: 707223
Change-Id: If52c0736daac3ad42ac6d324eb8ec5f1798f6f5a
Reviewed-on: https://chromium-review.googlesource.com/476630Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Franziska Hinkelmann <franzih@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44637}

src/feedback-vector.cc

@@ -911,7 +911,7 @@ InlineCacheState CollectTypeProfileNexus::StateFromFeedback() const {
 }
 
 void CollectTypeProfileNexus::Collect(Handle<String> type, int position) {
-  DCHECK_GT(position, 0);
+  DCHECK_GE(position, 0);
   Isolate* isolate = GetIsolate();
 
   Object* const feedback = GetFeedback();

src/list-inl.h

@@ -262,7 +262,7 @@ int SortedListBSearch(const List<T>& list, P cmp) {
       low = mid + 1;
       continue;
     }
-    // Found the elememt.
+    // Found the element.
     return mid;
   }
   return -1;

test/mjsunit/type-profile/regress-707223.js

+// Copyright 2017 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --type-profile
+
+let e;
+eval("e");