Fix crashing bug with session sync enabled and opening developer tools.

chrome/browser/ui/browser_synced_window_delegate.cc

Index: chrome/browser/ui/browser_synced_window_delegate.cc
diff --git a/chrome/browser/ui/browser_synced_window_delegate.cc b/chrome/browser/ui/browser_synced_window_delegate.cc
index d9a0947bc7e1de0f3577c5e724cb61fa39c5f227..91cb75c8f4c2a9f22c1cb78010043dfbcb08a1c6 100644
--- a/chrome/browser/ui/browser_synced_window_delegate.cc
+++ b/chrome/browser/ui/browser_synced_window_delegate.cc
@@ -29,7 +29,9 @@ const std::set<browser_sync::SyncedWindowDelegate*>
 const browser_sync::SyncedWindowDelegate*
     browser_sync::SyncedWindowDelegate::FindSyncedWindowDelegateWithId(
         SessionID::id_type id) {
-  return BrowserList::FindBrowserWithID(id)->synced_window_delegate();
+  Browser* browser = BrowserList::FindBrowserWithID(id);
+  // In case we don't find the browser (e.g. for Developer Tools).
+  return browser ? browser->synced_window_delegate() : NULL;
 }
 
 // BrowserSyncedWindowDelegate implementations