Call OwnerKeyUtil::FindPrivateKeyInSlot() in the blocking pool.

chrome/browser/chromeos/ownership/owner_settings_service_chromeos.cc

Index: chrome/browser/chromeos/ownership/owner_settings_service_chromeos.cc
diff --git a/chrome/browser/chromeos/ownership/owner_settings_service_chromeos.cc b/chrome/browser/chromeos/ownership/owner_settings_service_chromeos.cc
index 29b91ffb7be7255fee5d61f82100c73c5a2433b0..bbaa1120bbea9b77b01f320bc9c55e9a16e595ac 100644
--- a/chrome/browser/chromeos/ownership/owner_settings_service_chromeos.cc
+++ b/chrome/browser/chromeos/ownership/owner_settings_service_chromeos.cc
@@ -65,19 +65,14 @@ bool IsOwnerInTests(const std::string& user_id) {
   return static_cast<const base::Value*>(value)->GetString() == user_id;
 }
 
-void LoadPrivateKeyByPublicKey(
+void LoadPrivateKeyByPublicKeyOnWorkerThread(
     const scoped_refptr<OwnerKeyUtil>& owner_key_util,
     scoped_refptr<PublicKey> public_key,
-    const std::string& username_hash,
+    crypto::ScopedPK11Slot public_slot,
+    crypto::ScopedPK11Slot private_slot,
     const base::Callback<void(const scoped_refptr<PublicKey>& public_key,
                               const scoped_refptr<PrivateKey>& private_key)>&
         callback) {

[Daniel Erat, 2017/03/22 14:47:18]

can you DCHECK that this is running on the right thread here?

[Shuhei Takahashi, 2017/03/23 05:04:11]

Done.

-  crypto::EnsureNSSInit();
-  crypto::ScopedPK11Slot public_slot =
-      crypto::GetPublicSlotForChromeOSUser(username_hash);
-  crypto::ScopedPK11Slot private_slot = crypto::GetPrivateSlotForChromeOSUser(
-      username_hash, base::Callback<void(crypto::ScopedPK11Slot)>());
-
   // If private slot is already available, this will check it. If not, we'll get
   // called again later when the TPM Token is ready, and the slot will be
   // available then. FindPrivateKeyInSlot internally checks for a null slot if
@@ -98,6 +93,32 @@ void LoadPrivateKeyByPublicKey(
                           base::Bind(callback, public_key, private_key));
 }
 
+void LoadPrivateKeyByPublicKey(
+    const scoped_refptr<OwnerKeyUtil>& owner_key_util,
+    scoped_refptr<PublicKey> public_key,
+    const std::string& username_hash,
+    const base::Callback<void(const scoped_refptr<PublicKey>& public_key,
+                              const scoped_refptr<PrivateKey>& private_key)>&
+        callback) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+
+  crypto::EnsureNSSInit();
+  crypto::ScopedPK11Slot public_slot =
+      crypto::GetPublicSlotForChromeOSUser(username_hash);
+  crypto::ScopedPK11Slot private_slot = crypto::GetPrivateSlotForChromeOSUser(
+      username_hash, base::Callback<void(crypto::ScopedPK11Slot)>());
+
+  // This task interacts with the TPM, so use the blocking pool.
+  scoped_refptr<base::TaskRunner> task_runner =
+      BrowserThread::GetBlockingPool()->GetTaskRunnerWithShutdownBehavior(
+          base::SequencedWorkerPool::SKIP_ON_SHUTDOWN);
+  task_runner->PostTask(
+      FROM_HERE,
+      base::Bind(&LoadPrivateKeyByPublicKeyOnWorkerThread, owner_key_util,
+                 public_key, base::Passed(std::move(public_slot)),
+                 base::Passed(std::move(private_slot)), callback));
+}
+
 void LoadPrivateKey(
     const scoped_refptr<OwnerKeyUtil>& owner_key_util,
     const std::string username_hash,