[Panels] Fix favicon crash from using deleted WebContents.

chrome/browser/task_manager/task_manager_resource_providers.cc

Index: chrome/browser/task_manager/task_manager_resource_providers.cc
diff --git a/chrome/browser/task_manager/task_manager_resource_providers.cc b/chrome/browser/task_manager/task_manager_resource_providers.cc
index 687847104d23c861719190ebe509805abcb0a3e1..88a0f56cd75c8d06e011f4e1918e4dc04d300299 100644
--- a/chrome/browser/task_manager/task_manager_resource_providers.cc
+++ b/chrome/browser/task_manager/task_manager_resource_providers.cc
@@ -702,7 +702,7 @@ void TaskManagerPanelResourceProvider::Observe(int type,
       for (PanelResourceMap::iterator iter = resources_.begin();
            iter != resources_.end(); ++iter) {
         Panel* panel = iter->first;
-        if (panel->GetWebContents() == web_contents) {
+        if (!panel->GetWebContents()) {
           Remove(panel);
           break;
         }