Do not attempt to apply app sync updates to extensions with matching ID, or vice versa.

chrome/browser/extensions/extension_service_unittest.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/extensions/extension_service_unittest.h"
 
 #include <algorithm>
 #include <set>
 #include <vector>
 
@@ skipping 3522 matching lines @@
   EXPECT_TRUE(service_->GetExtensionById(good_crx, true));
 
   // Should uninstall the extension.
   service_->ProcessSyncData(extension_sync_data, &AllExtensions);
   EXPECT_FALSE(service_->GetExtensionById(good_crx, true));
 
   // Should again do nothing.
   service_->ProcessSyncData(extension_sync_data, &AllExtensions);
 }
 
+TEST_F(ExtensionServiceTest, ProcessSyncDataWrongType) {
+  InitializeEmptyExtensionService();
+
+  ExtensionSyncData extension_sync_data;
+  extension_sync_data.id = good_crx;
+  extension_sync_data.uninstalled = true;
+
+  // Install the extension.
+  FilePath extension_path = data_dir_.AppendASCII("good.crx");
+  InstallCrx(extension_path, true);
+  EXPECT_TRUE(service_->GetExtensionById(good_crx, true));
+
+  // Should do nothing
+  service_->ProcessSyncData(extension_sync_data, &ThemesOnly);
+  EXPECT_TRUE(service_->GetExtensionById(good_crx, true));
+
+  extension_sync_data.uninstalled = false;
+  extension_sync_data.enabled = false;
+
+  // Should again do nothing.
+  service_->ProcessSyncData(extension_sync_data, &ThemesOnly);
+  EXPECT_TRUE(service_->GetExtensionById(good_crx, false));
+}
 
 TEST_F(ExtensionServiceTest, ProcessSyncDataSettings) {
   InitializeEmptyExtensionService();
 
   InstallCrx(data_dir_.AppendASCII("good.crx"), true);
   EXPECT_TRUE(service_->IsExtensionEnabled(good_crx));
   EXPECT_FALSE(service_->IsIncognitoEnabled(good_crx));
 
   ExtensionSyncData extension_sync_data;
   extension_sync_data.id = good_crx;
@@ skipping 252 matching lines @@
   ASSERT_FALSE(AddPendingSyncInstall());
 
   // Wait for the external source to install.
   WaitForCrxInstall(crx_path_, true);
   ASSERT_TRUE(IsCrxInstalled());
 
   // Now that the extension is installed, sync request should fail
   // because the extension is already installed.
   ASSERT_FALSE(AddPendingSyncInstall());
 }