Introduce the plumbing necessary to report Unrecoverable error from model safe workers.

chrome/browser/sync/sessions/sync_session.h

Index: chrome/browser/sync/sessions/sync_session.h
diff --git a/chrome/browser/sync/sessions/sync_session.h b/chrome/browser/sync/sessions/sync_session.h
index 04b1a1a15b06104e0106e7f2cc8d1307aba2b85b..8fd949567e6df9c87c4452e5a762c7a759771ddf 100644
--- a/chrome/browser/sync/sessions/sync_session.h
+++ b/chrome/browser/sync/sessions/sync_session.h
@@ -22,12 +22,14 @@
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/location.h"
 #include "base/time.h"
 #include "chrome/browser/sync/engine/model_safe_worker.h"
 #include "chrome/browser/sync/sessions/ordered_commit_set.h"
 #include "chrome/browser/sync/sessions/session_state.h"
 #include "chrome/browser/sync/sessions/status_controller.h"
 #include "chrome/browser/sync/sessions/sync_session_context.h"
+#include "chrome/browser/sync/sessions/unrecoverable_error_info.h"
 #include "chrome/browser/sync/syncable/model_type.h"
 #include "chrome/browser/sync/util/extensions_activity_monitor.h"
 
@@ -90,6 +92,11 @@ class SyncSession {
     virtual void OnSyncProtocolError(
         const sessions::SyncSessionSnapshot& snapshot) = 0;
 
+    // Called when the syncer encounters an unrecoverable error.
+    virtual void OnUnrecoverableError(
+        const tracked_objects::Location& from_here,
+        const std::string& message) = 0;
+
    protected:
     virtual ~Delegate() {}
   };
@@ -146,6 +153,18 @@ class SyncSession {
   const ModelSafeRoutingInfo& routing_info() const { return routing_info_; }
   const SyncSourceInfo& source() const { return source_; }
 
+  // This can be called from any thread. We just cache the value of
+  // unrecoverable error info. When on the correct thread using this info
+  // delegate's OnUnrecoverableError method should be called.
+  void SetUnrecoverableError(const tracked_objects::Location& location,
+      const std::string& message,
+      syncable::BaseTransaction* trans);
+
+  bool unrecoverable_error() const { return unrecoverable_error_; }
+  UnrecoverableErrorInfo* unrecoverable_error_info() {
+    return unrecoverable_error_info_.get();
+  }
+
  private:
   // Extend the encapsulation boundary to utilities for internal member
   // assignments. This way, the scope of these actions is explicit, they can't
@@ -179,6 +198,9 @@ class SyncSession {
   // on those datatypes.
   ModelSafeRoutingInfo routing_info_;
 
+  scoped_ptr<UnrecoverableErrorInfo> unrecoverable_error_info_;
+  bool unrecoverable_error_;
+
   DISALLOW_COPY_AND_ASSIGN(SyncSession);
 };