Fix media galleries crash when the window is closed with config dialog open.

chrome/browser/extensions/api/media_galleries/media_galleries_api.cc

Index: chrome/browser/extensions/api/media_galleries/media_galleries_api.cc
diff --git a/chrome/browser/extensions/api/media_galleries/media_galleries_api.cc b/chrome/browser/extensions/api/media_galleries/media_galleries_api.cc
index 143096434049f2dd0f0a93cd83661e98d0f8056c..98f89cce98f198aa247ed01abfe876b9ad21e579 100644
--- a/chrome/browser/extensions/api/media_galleries/media_galleries_api.cc
+++ b/chrome/browser/extensions/api/media_galleries/media_galleries_api.cc
@@ -121,7 +121,12 @@ void MediaGalleriesGetMediaFileSystemsFunction::GetAndReturnGalleries() {
 
 void MediaGalleriesGetMediaFileSystemsFunction::ReturnGalleries(
     const std::vector<MediaFileSystemInfo>& filesystems) {
-  const int child_id = render_view_host()->GetProcess()->GetID();
+  content::RenderViewHost* rvh = render_view_host();
+  if (!rvh) {
+    SendResponse(false);
+    return;
+  }
+  const int child_id = rvh->GetProcess()->GetID();
   std::set<std::string> file_system_names;
   base::ListValue* list = new base::ListValue();
   for (size_t i = 0; i < filesystems.size(); i++) {