Clear up session only storage on localstorage shutdown

content/browser/dom_storage/dom_storage_context_wrapper.cc

Index: content/browser/dom_storage/dom_storage_context_wrapper.cc
diff --git a/content/browser/dom_storage/dom_storage_context_wrapper.cc b/content/browser/dom_storage/dom_storage_context_wrapper.cc
index 64964fe9e4fb6df6712067b3958b6b7836c66992..fbfda0dc61fb5cabb27ace3f32734d458e58f48a 100644
--- a/content/browser/dom_storage/dom_storage_context_wrapper.cc
+++ b/content/browser/dom_storage/dom_storage_context_wrapper.cc
@@ -126,14 +126,15 @@ DOMStorageContextWrapper::DOMStorageContextWrapper(
     base::FilePath storage_dir;
     if (!profile_path.empty())
       storage_dir = local_partition_path.AppendASCII(kLocalStorageDirectory);
-    // TODO(michaeln): Enable writing to disk when db is versioned,
-    // for now using an empty subdirectory to use an in-memory db.
-    // subdirectory_(subdirectory),
-    mojo_state_.reset(new LocalStorageContextMojo(
+    // TODO(mek): Use a SequencedTaskRunner once mojo no longer requires a
+    // SingleThreadTaskRunner (http://crbug.com/678155).
+    mojo_task_runner_ =
+        BrowserThread::GetTaskRunnerForThread(BrowserThread::IO);
+    mojo_state_ = new LocalStorageContextMojo(
         connector, context_->task_runner(),
         data_path.empty() ? data_path
                           : data_path.AppendASCII(kLocalStorageDirectory),
-        storage_dir));
+        storage_dir, special_storage_policy);
   }
 
   if (base::FeatureList::IsEnabled(features::kMemoryCoordinator)) {
@@ -144,14 +145,27 @@ DOMStorageContextWrapper::DOMStorageContextWrapper(
   }
 }
 
-DOMStorageContextWrapper::~DOMStorageContextWrapper() {}
+DOMStorageContextWrapper::~DOMStorageContextWrapper() {
+  DCHECK(!mojo_state_) << "Shutdown should be called before destruction";
+}
 
 void DOMStorageContextWrapper::GetLocalStorageUsage(
     const GetLocalStorageUsageCallback& callback) {
   DCHECK(context_.get());
   if (mojo_state_) {
-    mojo_state_->GetStorageUsage(base::BindOnce(
-        &DOMStorageContextWrapper::GotMojoLocalStorageUsage, this, callback));
+    // base::Unretained is safe here, because the mojo_state_ won't be deleted
+    // until a ShutdownAndDelete task has been ran on the mojo_task_runner_, and
+    // as soon as that task is posted, mojo_state_ is set to null, preventing
+    // further tasks from being queued.
+    mojo_task_runner_->PostTask(
+        FROM_HERE,
+        base::BindOnce(
+            &LocalStorageContextMojo::GetStorageUsage,
+            base::Unretained(mojo_state_),
+            base::BindOnce(
+                &DOMStorageContextWrapper::GotMojoLocalStorageUsage, this,
+                callback,
+                base::RetainedRef(base::ThreadTaskRunnerHandle::Get()))));
     return;
   }
   context_->task_runner()->PostShutdownBlockingTask(
@@ -179,8 +193,16 @@ void DOMStorageContextWrapper::DeleteLocalStorageForPhysicalOrigin(
       FROM_HERE, DOMStorageTaskRunner::PRIMARY_SEQUENCE,
       base::Bind(&DOMStorageContextImpl::DeleteLocalStorageForPhysicalOrigin,
                  context_, origin));
-  if (mojo_state_)
-    mojo_state_->DeleteStorageForPhysicalOrigin(url::Origin(origin));
+  if (mojo_state_) {
+    // base::Unretained is safe here, because the mojo_state_ won't be deleted
+    // until a ShutdownAndDelete task has been ran on the mojo_task_runner_, and
+    // as soon as that task is posted, mojo_state_ is set to null, preventing
+    // further tasks from being queued.
+    mojo_task_runner_->PostTask(
+        FROM_HERE,
+        base::BindOnce(&LocalStorageContextMojo::DeleteStorageForPhysicalOrigin,
+                       base::Unretained(mojo_state_), url::Origin(origin)));
+  }
 }
 
 void DOMStorageContextWrapper::DeleteLocalStorage(const GURL& origin) {
@@ -189,8 +211,16 @@ void DOMStorageContextWrapper::DeleteLocalStorage(const GURL& origin) {
       FROM_HERE,
       DOMStorageTaskRunner::PRIMARY_SEQUENCE,
       base::Bind(&DOMStorageContextImpl::DeleteLocalStorage, context_, origin));
-  if (mojo_state_)
-    mojo_state_->DeleteStorage(url::Origin(origin));
+  if (mojo_state_) {
+    // base::Unretained is safe here, because the mojo_state_ won't be deleted
+    // until a ShutdownAndDelete task has been ran on the mojo_task_runner_, and
+    // as soon as that task is posted, mojo_state_ is set to null, preventing
+    // further tasks from being queued.
+    mojo_task_runner_->PostTask(
+        FROM_HERE,
+        base::BindOnce(&LocalStorageContextMojo::DeleteStorage,
+                       base::Unretained(mojo_state_), url::Origin(origin)));
+  }
 }
 
 void DOMStorageContextWrapper::DeleteSessionStorage(
@@ -230,11 +260,26 @@ void DOMStorageContextWrapper::SetForceKeepSessionState() {
       FROM_HERE,
       DOMStorageTaskRunner::PRIMARY_SEQUENCE,
       base::Bind(&DOMStorageContextImpl::SetForceKeepSessionState, context_));
+  if (mojo_state_) {
+    // base::Unretained is safe here, because the mojo_state_ won't be deleted
+    // until a ShutdownAndDelete task has been ran on the mojo_task_runner_, and
+    // as soon as that task is posted, mojo_state_ is set to null, preventing
+    // further tasks from being queued.
+    mojo_task_runner_->PostTask(
+        FROM_HERE,
+        base::BindOnce(&LocalStorageContextMojo::SetForceKeepSessionState,
+                       base::Unretained(mojo_state_)));
+  }
 }
 
 void DOMStorageContextWrapper::Shutdown() {
   DCHECK(context_.get());
-  mojo_state_.reset();
+  if (mojo_state_) {
+    mojo_task_runner_->PostTask(
+        FROM_HERE, base::BindOnce(&LocalStorageContextMojo::ShutdownAndDelete,
+                                  base::Unretained(mojo_state_)));
+    mojo_state_ = nullptr;
+  }
   memory_pressure_listener_.reset();
   context_->task_runner()->PostShutdownBlockingTask(
       FROM_HERE,
@@ -248,11 +293,19 @@ void DOMStorageContextWrapper::Shutdown() {
 
 void DOMStorageContextWrapper::Flush() {
   DCHECK(context_.get());
+
   context_->task_runner()->PostShutdownBlockingTask(
       FROM_HERE, DOMStorageTaskRunner::PRIMARY_SEQUENCE,
       base::Bind(&DOMStorageContextImpl::Flush, context_));
-  if (mojo_state_)
-    mojo_state_->Flush();
+  if (mojo_state_) {
+    // base::Unretained is safe here, because the mojo_state_ won't be deleted
+    // until a ShutdownAndDelete task has been ran on the mojo_task_runner_, and
+    // as soon as that task is posted, mojo_state_ is set to null, preventing
+    // further tasks from being queued.
+    mojo_task_runner_->PostTask(FROM_HERE,
+                                base::BindOnce(&LocalStorageContextMojo::Flush,
+                                               base::Unretained(mojo_state_)));
+  }
 }
 
 void DOMStorageContextWrapper::OpenLocalStorage(
@@ -260,7 +313,14 @@ void DOMStorageContextWrapper::OpenLocalStorage(
     mojom::LevelDBWrapperRequest request) {
   if (!mojo_state_)
     return;
-  mojo_state_->OpenLocalStorage(origin, std::move(request));
+  // base::Unretained is safe here, because the mojo_state_ won't be deleted
+  // until a ShutdownAndDelete task has been ran on the mojo_task_runner_, and
+  // as soon as that task is posted, mojo_state_ is set to null, preventing
+  // further tasks from being queued.
+  mojo_task_runner_->PostTask(
+      FROM_HERE, base::BindOnce(&LocalStorageContextMojo::OpenLocalStorage,
+                                base::Unretained(mojo_state_), origin,
+                                std::move(request)));
 }
 
 void DOMStorageContextWrapper::OnMemoryPressure(
@@ -283,17 +343,25 @@ void DOMStorageContextWrapper::PurgeMemory(DOMStorageContextImpl::PurgeOption
   context_->task_runner()->PostTask(
       FROM_HERE,
       base::Bind(&DOMStorageContextImpl::PurgeMemory, context_, purge_option));
-  if (mojo_state_ && purge_option == DOMStorageContextImpl::PURGE_AGGRESSIVE)
-    mojo_state_->PurgeMemory();
+  if (mojo_state_ && purge_option == DOMStorageContextImpl::PURGE_AGGRESSIVE) {
+    // base::Unretained is safe here, because the mojo_state_ won't be deleted
+    // until a ShutdownAndDelete task has been ran on the mojo_task_runner_, and
+    // as soon as that task is posted, mojo_state_ is set to null, preventing
+    // further tasks from being queued.
+    mojo_task_runner_->PostTask(
+        FROM_HERE, base::BindOnce(&LocalStorageContextMojo::PurgeMemory,
+                                  base::Unretained(mojo_state_)));
+  }
 }
 
 void DOMStorageContextWrapper::GotMojoLocalStorageUsage(
     GetLocalStorageUsageCallback callback,
+    base::SingleThreadTaskRunner* reply_task_runner,
     std::vector<LocalStorageUsageInfo> usage) {
   context_->task_runner()->PostShutdownBlockingTask(
       FROM_HERE, DOMStorageTaskRunner::PRIMARY_SEQUENCE,
       base::Bind(&GetLocalStorageUsageHelper, base::Passed(&usage),
-                 base::RetainedRef(base::ThreadTaskRunnerHandle::Get()),
+                 base::RetainedRef(reply_task_runner),
                  base::RetainedRef(context_), callback));
 }