Fix a bunch of tiny near-bugs and bugs that static analysis identified...

base/stats_table.cc

Index: base/stats_table.cc
===================================================================
--- base/stats_table.cc	(revision 12136)
+++ base/stats_table.cc	(working copy)
@@ -502,9 +502,9 @@
 
   int rv = 0;
   int* row = impl_->row(index);
-  for (int index = 0; index < impl_->max_threads(); index++) {
-    if (pid == 0 || *impl_->thread_pid(index) == pid)
-      rv += row[index];
+  for (int slot_id = 0; slot_id < impl_->max_threads(); slot_id++) {
+    if (pid == 0 || *impl_->thread_pid(slot_id) == pid)
+      rv += row[slot_id];
   }
   return rv;
 }