[sql] Stats gathering for sql/ APIs.

sql/statement.h

Index: sql/statement.h
diff --git a/sql/statement.h b/sql/statement.h
index b411e809b6ca9cee8f6792cb7135db81f2d6fc92..6091a552141c341bd31a962e10c9661260743e90 100644
--- a/sql/statement.h
+++ b/sql/statement.h
@@ -150,6 +150,8 @@ class SQL_EXPORT Statement {
   const char* GetSQLStatement();
 
  private:
+  friend class Connection;
+
   // This is intended to check for serious errors and report them to the
   // connection object. It takes a sqlite error code, and returns the same
   // code. Currently this function just updates the succeeded flag, but will be
@@ -174,6 +176,14 @@ class SQL_EXPORT Statement {
   // ensuring that contracts are honored in error edge cases.
   bool CheckValid() const;
 
+  // Helper for Run() and Step(), calls sqlite3_step() and histograms based on
+  // the results.  The checked value from sqlite3_step() is returned.

[rmcilroy, 2015/05/21 22:54:48]

"and histograms based on the results if |timer_flag| is true."

[Scott Hess - ex-Googler, 2015/05/21 23:42:37]

Done, maybe, but in terms of "How would I use this" I'm not sure it helps :-).

+  int InnerStep(bool timer_flag);

[rmcilroy, 2015/05/21 22:54:48]

Maybe call StepInternal would be clearer?

[Scott Hess - ex-Googler, 2015/05/21 23:42:37]

Done.

+
+  // sql::Connection uses cached statments for transactions, but tracks their
+  // runtime independently.
+  bool RunWithoutTimers();
+
   // The actual sqlite statement. This may be unique to us, or it may be cached
   // by the connection, which is why it's refcounted. This pointer is
   // guaranteed non-NULL.