[sql] Move time-machine support from third_party/sqlite to sql/

sql/connection.cc

Index: sql/connection.cc
diff --git a/sql/connection.cc b/sql/connection.cc
index d220c8e8d78906aad8f9064bd752ea811ec43cf6..a4fa48f534c3af60ac527b830f51b2347949027b 100644
--- a/sql/connection.cc
+++ b/sql/connection.cc
@@ -33,6 +33,7 @@
 #include "sql/connection_memory_dump_provider.h"
 #include "sql/meta_table.h"
 #include "sql/statement.h"
+#include "sql/vfs_wrapper.h"
 #include "third_party/sqlite/sqlite3.h"
 
 #if defined(OS_IOS) && defined(USE_SYSTEM_SQLITE)
@@ -40,8 +41,24 @@
 #include "third_party/sqlite/src/ext/icu/sqliteicu.h"
 #endif
 
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+#include <CoreFoundation/CoreFoundation.h>
+#include <CoreServices/CoreServices.h>
+#endif
+
 namespace {
 
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+void gross() {
+  CFPreferencesSetAppValue(CFSTR("CSBackupDebugLogging"),
+                           kCFBooleanTrue,
+                           kCFPreferencesCurrentApplication);
+}
+#else
+void gross() {
+}
+#endif
+
 // 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
@@ -159,6 +176,7 @@ void InitializeSqlite() {
   base::AutoLock lock(g_sqlite_init_lock.Get());
   static bool first_call = true;
   if (first_call) {
+    gross();
     sqlite3_initialize();
 
     // Schedule callback to record memory footprint histograms at 10m, 1h, and
@@ -1690,7 +1708,12 @@ bool Connection::OpenInternal(const std::string& file_name,
   DLOG_IF(FATAL, poisoned_) << "sql::Connection is already open.";
   poisoned_ = false;
 
-  int err = sqlite3_open(file_name.c_str(), &db_);
+  // Custom memory-mapping VFS which reads pages using regular I/O on first hit.
+  sqlite3_vfs* vfs = VFSWrapper();
+  const char* vfs_name = (vfs ? vfs->zName : NULL);
+  int err = sqlite3_open_v2(file_name.c_str(), &db_,
+                            SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE,
+                            vfs_name);
   if (err != SQLITE_OK) {
     // Extended error codes cannot be enabled until a handle is
     // available, fetch manually.