Updates SQL code now that mmap is supported on iOS.

sql/connection.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "sql/connection.h"
 
 #include <limits.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <string.h>
@@ skipping 18 matching lines @@
 #include "base/strings/utf_string_conversions.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/trace_event/memory_dump_manager.h"
 #include "sql/connection_memory_dump_provider.h"
 #include "sql/meta_table.h"
 #include "sql/statement.h"
 #include "third_party/sqlite/sqlite3.h"
 
 #if defined(OS_IOS) && defined(USE_SYSTEM_SQLITE)
+#include "base/ios/ios_util.h"
 #include "third_party/sqlite/src/ext/icu/sqliteicu.h"
 #endif
 
 namespace {
 
 // Spin for up to a second waiting for the lock to clear when setting
 // up the database.
 // TODO(shess): Better story on this.  http://crbug.com/56559
 const int kBusyTimeoutSeconds = 1;
 
@@ skipping 801 matching lines @@
       base::StringAppendF(&debug_info, "%s\n", messages[i].c_str());
     }
   }
 
   return debug_info;
 }
 
 size_t Connection::GetAppropriateMmapSize() {
   AssertIOAllowed();
 
-#if defined(OS_IOS)
-  // iOS SQLite does not support memory mapping.
-  return 0;
+#if defined(OS_IOS) && defined(USE_SYSTEM_SQLITE)
+  if (!base::ios::IsRunningOnIOS10OrLater()) {
+    // iOS SQLite does not support memory mapping.
+    return 0;
+  }
 #endif
 
   // How much to map if no errors are found.  50MB encompasses the 99th
   // percentile of Chrome databases in the wild, so this should be good.
   const size_t kMmapEverything = 256 * 1024 * 1024;
 
   // If the database doesn't have a place to track progress, assume the best.
   // This will happen when new databases are created, or if a database doesn't
   // use a meta table.  sql::MetaTable::Init() will preload kMmapSuccess.
   // TODO(shess): Databases not using meta include:
@@ skipping 1079 matching lines @@
   ignore_result(Execute(kNoWritableSchema));
 
   return ret;
 }
 
 base::TimeTicks TimeSource::Now() {
   return base::TimeTicks::Now();
 }
 
 }  // namespace sql