Fixing guest processes to use the proper storage partition.

content/browser/storage_partition_impl_map.cc

Index: content/browser/storage_partition_impl_map.cc
diff --git a/content/browser/storage_partition_impl_map.cc b/content/browser/storage_partition_impl_map.cc
index 77fb9239c9063bd32de0e793a5d87b9b5bf1c5aa..43aec42a60d18ec581ae4b58d7df331b463ca90a 100644
--- a/content/browser/storage_partition_impl_map.cc
+++ b/content/browser/storage_partition_impl_map.cc
@@ -204,10 +204,15 @@ StoragePartitionImpl* StoragePartitionImplMap::Get(
   if (it != partitions_.end())
     return it->second;
 
-  // There was no previous partition, so let's make a new one.
+  // There was no previous partition, so let's make a new one. The storage
+  // partition should be in memory for guest processes and OTR profiles.
+  bool in_memory = browser_context_->IsOffTheRecord() ||
+      StartsWithASCII(partition_id, "guest-", true);
+
   StoragePartitionImpl* partition =
       StoragePartitionImpl::Create(browser_context_, partition_id,
-                                   browser_context_->GetPath());
+                                   browser_context_->GetPath(),
+                                   in_memory);
   partitions_[partition_id] = partition;
 
   // These calls must happen after StoragePartitionImpl::Create().