sync: Add NonBlockingTypeProcesssor and SyncCore

Introduces the model-thread sibling of the NonBlockingTypeProcessorCore
that was added in r258390.  Also adds SyncCore and SyncCoreProxy, the
classes that will be used to connect the two.

The SyncCore lives on the sync thread and carries out requests sent to
it by the SyncCoreProxy.  The SyncCoreProxy is a thread-safe wrapper
around the SyncCore that can be easily copied and whose methods can be
called from any thread.

The NonBlockingTypeProcessor is instantiated on the same thread as the
data to be synced.  It connects to a NonBlockingTypeProcessorCore on the
sync thread by sending a request through a SyncCoreProxy.  Keeping data
in sync will be a collaborative effort involving both the
NonBlockingTypeProcessor and NonBlockingTypeProcesssorCore, though none
of this functionality has been implemented yet.

As of this CL, none these classes are instantiated outside of tests.
This CL should have no effect on current sync behavior.

BUG=351005

Review URL: https://codereview.chromium.org/208893004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@259921 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 21 insertions, 3 deletions

diff --git a/sync/engine/non_blocking_type_processor_core.cc b/sync/engine/non_blocking_type_processor_core.cc
index 6d6abc4..fdb9e10 100644
--- a/sync/engine/non_blocking_type_processor_core.cc
+++ b/sync/engine/non_blocking_type_processor_core.cc
@@ -10,7 +10,13 @@
 namespace syncer {
 
 NonBlockingTypeProcessorCore::NonBlockingTypeProcessorCore(
-    ModelType type) : type_(type), weak_ptr_factory_(this) {
+      ModelType type,
+      scoped_refptr<base::SequencedTaskRunner> processor_task_runner,
+      base::WeakPtr<NonBlockingTypeProcessor> processor)
+    : type_(type),
+      processor_task_runner_(processor_task_runner),
+      processor_(processor),
+      weak_ptr_factory_(this) {
   progress_marker_.set_data_type_id(GetSpecificsFieldNumberFromModelType(type));
 }
 
diff --git a/sync/engine/non_blocking_type_processor_core.h b/sync/engine/non_blocking_type_processor_core.h
index 028bb3a..412d2dd 100644
--- a/sync/engine/non_blocking_type_processor_core.h
+++ b/sync/engine/non_blocking_type_processor_core.h
@@ -13,8 +13,14 @@
 #include "sync/internal_api/public/base/model_type.h"
 #include "sync/protocol/sync.pb.h"
 
+namespace base {
+class SingleThreadTaskRunner;
+}
+
 namespace syncer {
 
+class NonBlockingTypeProcessor;
+
 // A smart cache for sync types that use message passing (rather than
 // transactions and the syncable::Directory) to communicate with the sync
 // thread.
@@ -35,12 +41,15 @@ namespace syncer {
 // example, if the sync server sends down an update for a sync entity that is
 // currently pending for commit, this object will detect this condition and
 // cancel the pending commit.
-class SYNC_EXPORT_PRIVATE NonBlockingTypeProcessorCore
+class SYNC_EXPORT NonBlockingTypeProcessorCore
     : public UpdateHandler,
       public CommitContributor,
       public base::NonThreadSafe {
  public:
-  explicit NonBlockingTypeProcessorCore(ModelType type);
+  NonBlockingTypeProcessorCore(
+      ModelType type,
+      scoped_refptr<base::SequencedTaskRunner> processor_task_runner,
+      base::WeakPtr<NonBlockingTypeProcessor> processor);
   virtual ~NonBlockingTypeProcessorCore();
 
   ModelType GetModelType() const;
@@ -65,6 +74,9 @@ class SYNC_EXPORT_PRIVATE NonBlockingTypeProcessorCore
   ModelType type_;
   sync_pb::DataTypeProgressMarker progress_marker_;
 
+  scoped_refptr<base::SequencedTaskRunner> processor_task_runner_;
+  base::WeakPtr<NonBlockingTypeProcessor> processor_;
+
   base::WeakPtrFactory<NonBlockingTypeProcessorCore> weak_ptr_factory_;
 };