[Sync] Initial support for encrypting any datatype (no UI hookup yet).

chrome/browser/sync/glue/session_change_processor.cc

Index: chrome/browser/sync/glue/session_change_processor.cc
diff --git a/chrome/browser/sync/glue/session_change_processor.cc b/chrome/browser/sync/glue/session_change_processor.cc
index 8823af0664cbaa1001a9413617826f0d287bf798..56a99fb958a50a13892b895d51cf2dfd32ea7f2c 100644
--- a/chrome/browser/sync/glue/session_change_processor.cc
+++ b/chrome/browser/sync/glue/session_change_processor.cc
@@ -10,8 +10,10 @@
 
 #include "base/logging.h"
 #include "base/scoped_vector.h"
+#include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/session_model_associator.h"
+#include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/tab_contents/navigation_controller.h"
 #include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/common/notification_details.h"
@@ -31,6 +33,19 @@ SessionChangeProcessor::SessionChangeProcessor(
   DCHECK(session_model_associator_);
 }
 
+SessionChangeProcessor::SessionChangeProcessor(
+    UnrecoverableErrorHandler* error_handler,
+    SessionModelAssociator* session_model_associator,
+    bool setup_for_test)
+    : ChangeProcessor(error_handler),
+      session_model_associator_(session_model_associator),
+      profile_(NULL),
+      setup_for_test_(setup_for_test) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(error_handler);
+  DCHECK(session_model_associator_);
+}
+
 SessionChangeProcessor::~SessionChangeProcessor() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 }
@@ -183,6 +198,15 @@ void SessionChangeProcessor::ApplyChangesFromSyncModel(
 
     const sync_pb::SessionSpecifics& specifics(
         sync_node.GetSessionSpecifics());
+    if (specifics.session_tag() ==
+            session_model_associator_->GetCurrentMachineTag() &&
+        !setup_for_test_) {
+      // We should only ever receive a change to our own machine's session info
+      // if encryption was turned on. In that case, the data is still the same,
+      // so we can ignore.
+      LOG(WARNING) << "Dropping modification to local session.";
+      return;
+    }
     const int64 mtime = sync_node.GetModificationTime();
     // Model associator handles foreign session update and add the same.
     session_model_associator_->AssociateForeignSpecifics(specifics, mtime);