Don't stomp on non-sync pending updates.

chrome/browser/extensions/extensions_service.cc

 // Copyright (c) 2010 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/extensions_service.h"
 
 #include <algorithm>
 
 #include "base/basictypes.h"
 #include "base/command_line.h"
@@ skipping 735 matching lines @@
 }
 
 void ExtensionsService::AddPendingExtensionInternal(
     const std::string& id, const GURL& update_url,
     PendingExtensionInfo::ExpectedCrxType expected_crx_type,
     bool is_from_sync, bool install_silently,
     bool enable_on_install, bool enable_incognito_on_install,
     Extension::Location install_source) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
+  // If a non-sync update is pending, a sync request should not
+  // overwrite it.  This is important for external extensions.
+  // If an external extension download is pending, and the user has
+  // the extension in their sync profile, the install should set the
+  // type to be external.  An external extension should not be
+  // rejected if it fails the safty checks for a syncable extension.
+  // TODO(skerner): Work out other potential overlapping conditions.
+  // (crbug/61000)
+  PendingExtensionMap::iterator it = pending_extensions_.find(id);
+  if (it != pending_extensions_.end()) {
+    VLOG(1) << "Extension id " << id
+            << " was entered for update more than once."
+            << "  old is_from_sync = " << it->second.is_from_sync
+            << "  new is_from_sync = " << is_from_sync;
+    if (!it->second.is_from_sync && is_from_sync)
+      return;
+  }
+
+
   pending_extensions_[id] =
       PendingExtensionInfo(update_url, expected_crx_type, is_from_sync,
                            install_silently, enable_on_install,
                            enable_incognito_on_install, install_source);
 }
 
 void ExtensionsService::ReloadExtension(const std::string& extension_id) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   FilePath path;
   const Extension* current_extension = GetExtensionById(extension_id, false);
@@ skipping 1105 matching lines @@
 ExtensionIdSet ExtensionsService::GetAppIds() const {
   ExtensionIdSet result;
   for (ExtensionList::const_iterator it = extensions_.begin();
        it != extensions_.end(); ++it) {
     if ((*it)->is_app() && (*it)->location() != Extension::COMPONENT)
       result.insert((*it)->id());
   }
 
   return result;
 }