[sql] Framework for allowing tests to handle errors.

sql/connection.h

Index: sql/connection.h
diff --git a/sql/connection.h b/sql/connection.h
index 049d7cf5b4e2f9715ffc4b7f67dd2e89dc367bff..920143157afe004bf1605e75e2dbe04d207adef5 100644
--- a/sql/connection.h
+++ b/sql/connection.h
@@ -13,6 +13,7 @@
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/compiler_specific.h"
+#include "base/lazy_instance.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/threading/thread_restrictions.h"
@@ -376,6 +377,9 @@ class SQL_EXPORT Connection {
   const char* GetErrorMessage() const;
 
  private:
+  // Allow test-support code to set/reset error ignorer.
+  friend class ScopedErrorIgnorer;
+
   // Statement accesses StatementRef which we don't want to expose to everybody
   // (they should go through Statement).
   friend class Statement;
@@ -400,6 +404,14 @@ class SQL_EXPORT Connection {
   // Internal helper for DoesTableExist and DoesIndexExist.
   bool DoesTableOrIndexExist(const char* name, const char* type) const;
 
+  // Accessors for global error-ignorer, for injecting behavior during tests.
+  // See test/scoped_error_ignorer.h.
+  typedef base::Callback<bool(int)> ErrorIgnorerCallback;
+  static base::LazyInstance<ErrorIgnorerCallback> current_ignorer_cb_;
+  static bool ShouldIgnore(int error);
+  static void SetErrorIgnorer(const ErrorIgnorerCallback& ignorer);
+  static void ResetErrorIgnorer();
+
   // A StatementRef is a refcounted wrapper around a sqlite statement pointer.
   // Refcounting allows us to give these statements out to sql::Statement
   // objects while also optionally maintaining a cache of compiled statements