Set proto database provider for incognito profile key

The Android services use profile key to get provider and the provider in
the key should be valid for incognito profile too.

BUG=1124790

Change-Id: I392956f2b587fdf82a910a8b7db959c057f81cb3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2432212
Commit-Queue: ssid <ssid@chromium.org>
Commit-Queue: Tommy Nyquist <nyquist@chromium.org>
Reviewed-by: Tommy Nyquist <nyquist@chromium.org>
Cr-Commit-Position: refs/heads/master@{#810885}

chrome/browser/profiles/off_the_record_profile_impl.cc

@@ -182,6 +182,9 @@ void OffTheRecordProfileImpl::Init() {
   AccessibilityLabelsService::InitOffTheRecordPrefs(this);
 
   HeavyAdServiceFactory::GetForBrowserContext(this)->InitializeOffTheRecord();
+
+  key_->SetProtoDatabaseProvider(
+      GetDefaultStoragePartition(this)->GetProtoDatabaseProvider());
 }
 
 OffTheRecordProfileImpl::~OffTheRecordProfileImpl() {