Purge browser cache for dom storage in a smarter way

content/browser/dom_storage/dom_storage_context_wrapper.cc

 // Copyright 2013 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 "content/browser/dom_storage/dom_storage_context_wrapper.h"
 
 #include <string>
 #include <vector>
 
 #include "base/bind.h"
@@ skipping 267 matching lines @@
                         : data_path.AppendASCII(kLocalStorageDirectory),
       data_path.empty() ? data_path
                         : data_path.AppendASCII(kSessionStorageDirectory),
       special_storage_policy,
       new DOMStorageWorkerPoolTaskRunner(
           worker_pool,
           worker_pool->GetNamedSequenceToken("dom_storage_primary"),
           worker_pool->GetNamedSequenceToken("dom_storage_commit"),
           BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO)
               .get()));
+
+  memory_pressure_listener_.reset(new base::MemoryPressureListener(
+      base::Bind(&DOMStorageContextWrapper::OnMemoryPressure, this)));
 }
 
 DOMStorageContextWrapper::~DOMStorageContextWrapper() {}
 
 void DOMStorageContextWrapper::GetLocalStorageUsage(
     const GetLocalStorageUsageCallback& callback) {
   DCHECK(context_.get());
   context_->task_runner()->PostShutdownBlockingTask(
       FROM_HERE, DOMStorageTaskRunner::PRIMARY_SEQUENCE,
       base::Bind(&GetLocalStorageUsageHelper,
@@ skipping 54 matching lines @@
   DCHECK(context_.get());
   context_->task_runner()->PostShutdownBlockingTask(
       FROM_HERE,
       DOMStorageTaskRunner::PRIMARY_SEQUENCE,
       base::Bind(&DOMStorageContextImpl::SetForceKeepSessionState, context_));
 }
 
 void DOMStorageContextWrapper::Shutdown() {
   DCHECK(context_.get());
   mojo_state_.reset();
+  memory_pressure_listener_.reset();
   context_->task_runner()->PostShutdownBlockingTask(
       FROM_HERE,
       DOMStorageTaskRunner::PRIMARY_SEQUENCE,
       base::Bind(&DOMStorageContextImpl::Shutdown, context_));
 }
 
 void DOMStorageContextWrapper::Flush() {
   DCHECK(context_.get());
   context_->task_runner()->PostShutdownBlockingTask(
       FROM_HERE, DOMStorageTaskRunner::PRIMARY_SEQUENCE,
       base::Bind(&DOMStorageContextImpl::Flush, context_));
 }
 
 void DOMStorageContextWrapper::OpenLocalStorage(
     const url::Origin& origin,
     mojom::LevelDBObserverPtr observer,
     mojom::LevelDBWrapperRequest request) {
   mojo_state_->OpenLocalStorage(
       origin, std::move(observer), std::move(request));
 }
 
+void DOMStorageContextWrapper::OnMemoryPressure(
+    base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level) {
+  DOMStorageContextImpl::PurgeOption purge_option =
+      DOMStorageContextImpl::PURGE_UNOPENED;
+  if (memory_pressure_level ==
+      base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL) {
+    purge_option = DOMStorageContextImpl::PURGE_AGGRESSIVE;
+  }
+  context_->task_runner()->PostTask(
+      FROM_HERE,
+      base::Bind(&DOMStorageContextImpl::PurgeMemory, context_, purge_option));
+}
+
 }  // namespace content