Stab-in-the-dark at fixing a top crasher. GetCurrentRenderView() can

chrome/renderer/extensions/extension_process_bindings.cc

Index: chrome/renderer/extensions/extension_process_bindings.cc
diff --git a/chrome/renderer/extensions/extension_process_bindings.cc b/chrome/renderer/extensions/extension_process_bindings.cc
index e3cfe0a764baf3aa2ddfe01a1e3234e2036c8d43..58c301db98237e73a0a5d126f9443df208a3fd08 100644
--- a/chrome/renderer/extensions/extension_process_bindings.cc
+++ b/chrome/renderer/extensions/extension_process_bindings.cc
@@ -204,11 +204,14 @@ class ExtensionImpl : public ExtensionBase {
   // be an extension URL.
   static std::string ExtensionIdForCurrentContext() {
     RenderView* renderview = bindings_utils::GetRenderViewForCurrentContext();
-    DCHECK(renderview);
+    if (!renderview)
+      return std::string();  // this can happen as a tab is closing.
+
     GURL url = renderview->webview()->mainFrame()->url();
-    if (url.SchemeIs(chrome::kExtensionScheme))
-      return url.host();
-    return std::string();
+    if (!url.SchemeIs(chrome::kExtensionScheme))
+      return std::string();
+
+    return url.host();
   }
 
   virtual v8::Handle<v8::FunctionTemplate> GetNativeFunction(
@@ -272,7 +275,11 @@ class ExtensionImpl : public ExtensionBase {
     }
 
     int browser_window_id = render_view->browser_window_id();
-    ExtensionViewAccumulator  popup_matcher(ExtensionIdForCurrentContext(),
+    std::string extension_id = ExtensionIdForCurrentContext();
+    if (extension_id.empty())
+      return v8::Undefined();
+
+    ExtensionViewAccumulator  popup_matcher(extension_id,
                                             browser_window_id,
                                             viewtype_to_find);
     RenderView::ForEach(&popup_matcher);
@@ -321,8 +328,12 @@ class ExtensionImpl : public ExtensionBase {
       return v8::Undefined();
     }
 
-    ExtensionViewAccumulator accumulator(
-        ExtensionIdForCurrentContext(), browser_window_id, view_type);
+    std::string extension_id = ExtensionIdForCurrentContext();
+    if (extension_id.empty())
+      return v8::Undefined();
+
+    ExtensionViewAccumulator accumulator(extension_id, browser_window_id,
+                                         view_type);
     RenderView::ForEach(&accumulator);
     return accumulator.views();
   }
@@ -383,8 +394,11 @@ class ExtensionImpl : public ExtensionBase {
       return v8::Undefined();
     }
 
-    L10nMessagesMap* l10n_messages =
-      GetL10nMessagesMap(ExtensionIdForCurrentContext());
+    std::string extension_id = ExtensionIdForCurrentContext();
+    if (extension_id.empty())
+      return v8::Undefined();
+
+    L10nMessagesMap* l10n_messages = GetL10nMessagesMap(extension_id);
     if (!l10n_messages)
       return v8::Undefined();
 
@@ -641,6 +655,9 @@ static std::string GetPermissionName(const std::string& function_name) {
 bool ExtensionProcessBindings::CurrentContextHasPermission(
     const std::string& function_name) {
   std::string extension_id = ExtensionImpl::ExtensionIdForCurrentContext();
+  if (extension_id.empty())
+    return false;
+
   PermissionsMap& permissions_map = *GetPermissionsMap(extension_id);
   std::string permission_name = GetPermissionName(function_name);
   PermissionsMap::iterator it = permissions_map.find(permission_name);