Connect SimpleCache Backend active_entries_ more closely to Entry lifetime.

net/disk_cache/simple/simple_entry_impl.cc

Index: net/disk_cache/simple/simple_entry_impl.cc
diff --git a/net/disk_cache/simple/simple_entry_impl.cc b/net/disk_cache/simple/simple_entry_impl.cc
index dc395d67e84eac208ad8465809331bb07dc867ac..5dbc4dcc4ed4101a0df333ba7c8fbd572aac99eb 100644
--- a/net/disk_cache/simple/simple_entry_impl.cc
+++ b/net/disk_cache/simple/simple_entry_impl.cc
@@ -161,6 +161,8 @@ class SimpleEntryImpl::ScopedOperationRunner {
   SimpleEntryImpl* const entry_;
 };
 
+SimpleEntryImpl::BackendDisconnector::~BackendDisconnector() {}
+
 SimpleEntryImpl::SimpleEntryImpl(net::CacheType cache_type,
                                  const FilePath& path,
                                  const uint64 entry_hash,
@@ -196,6 +198,12 @@ SimpleEntryImpl::SimpleEntryImpl(net::CacheType cache_type,
       CreateNetLogSimpleEntryConstructionCallback(this));
 }
 
+void SimpleEntryImpl::SetBackendDisconnector(
+    scoped_ptr<BackendDisconnector> backend_disconnector) {
+  DCHECK(!backend_disconnector_);
+  backend_disconnector_.reset(backend_disconnector.release());
+}
+
 int SimpleEntryImpl::OpenEntry(Entry** out_entry,
                                const CompletionCallback& callback) {
   DCHECK(backend_.get());
@@ -526,7 +534,6 @@ SimpleEntryImpl::~SimpleEntryImpl() {
   DCHECK_EQ(0U, pending_operations_.size());
   DCHECK(state_ == STATE_UNINITIALIZED || state_ == STATE_FAILURE);
   DCHECK(!synchronous_entry_);
-  RemoveSelfFromBackend();
   net_log_.EndEvent(net::NetLog::TYPE_SIMPLE_CACHE_ENTRY);
 }
 
@@ -568,18 +575,12 @@ void SimpleEntryImpl::ReturnEntryToCaller(Entry** out_entry) {
   *out_entry = this;
 }
 
-void SimpleEntryImpl::RemoveSelfFromBackend() {
-  if (!backend_.get())
-    return;
-  backend_->OnDeactivated(this);
-}
-
 void SimpleEntryImpl::MarkAsDoomed() {
   doomed_ = true;
   if (!backend_.get())
     return;
   backend_->index()->Remove(entry_hash_);
-  RemoveSelfFromBackend();
+  backend_disconnector_.reset();

[Deprecated (see juliatuttle), 2014/08/22 19:26:38]

I'd like a comment here making it clear that resetting the disconnector causes
it to disconnect. (That, or name it auto_disconnector or scoped_disconnector or
something that makes the behavior more inherently clear. Actually, calling it
Connector or Connection or something, since it destroys the connection when it
is destroyed, might make more sense?)

[gavinp, 2014/08/25 13:18:27]

I like your suggestion we rename this; I have gone a bit farther and renamed the
class, too.

I'm calling it "ActiveEntryProxy" now. This bleeds a bit of the abstraction from
the backend to the entry, but the name makes the flow a lot clearer; the pure
virtual base class abstraction avoids bleeding the design as heavily in to the
code as it was before, which makes getting the special cases right easier.

 }
 
 void SimpleEntryImpl::RunNextOperationIfNeeded() {