Adds a MemoryPressureListener to sql::Connection.

This will allow SQLite database to reduce their page cache memory on systems
which provide a MemoryPressureListener signal.

BUG=243769

Review URL: https://chromiumcodereview.appspot.com/17071007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@212374 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 14 insertions, 0 deletions

diff --git a/chrome/browser/history/history_backend.cc b/chrome/browser/history/history_backend.cc
index a5a0cca..adaff5a 100644
--- a/chrome/browser/history/history_backend.cc
+++ b/chrome/browser/history/history_backend.cc
@@ -260,6 +260,8 @@ void HistoryBackend::Init(const std::string& languages, bool force_fail) {
     InitImpl(languages);
   delegate_->DBLoaded(id_);
   typed_url_syncable_service_.reset(new TypedUrlSyncableService(this));
+  memory_pressure_listener_.reset(new base::MemoryPressureListener(
+      base::Bind(&HistoryBackend::OnMemoryPressure, base::Unretained(this))));
 #if defined(OS_ANDROID)
   PopulateMostVisitedURLMap();
 #endif
@@ -766,6 +768,18 @@ void HistoryBackend::InitImpl(const std::string& languages) {
                   TimeTicks::Now() - beginning_time);
 }
 
+void HistoryBackend::OnMemoryPressure(
+    base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level) {
+  bool trim_aggressively = memory_pressure_level ==
+      base::MemoryPressureListener::MEMORY_PRESSURE_CRITICAL;
+  if (db_)
+    db_->TrimMemory(trim_aggressively);
+  if (thumbnail_db_)
+    thumbnail_db_->TrimMemory(trim_aggressively);
+  if (archived_db_)
+    archived_db_->TrimMemory(trim_aggressively);
+}
+
 void HistoryBackend::CloseAllDatabases() {
   if (db_) {
     // Commit the long-running transaction.