Have LazyBackgroundTaskQueue notify consumers when the transient page fails to

chrome/browser/extensions/api/runtime/runtime_api.cc

Index: chrome/browser/extensions/api/runtime/runtime_api.cc
diff --git a/chrome/browser/extensions/api/runtime/runtime_api.cc b/chrome/browser/extensions/api/runtime/runtime_api.cc
index 544e064ac42b18472f5194d805a70753b8a680f2..9e6998ec67cbf8361a5ebe14f9db71aed7d0bfa9 100644
--- a/chrome/browser/extensions/api/runtime/runtime_api.cc
+++ b/chrome/browser/extensions/api/runtime/runtime_api.cc
@@ -17,6 +17,7 @@ namespace {
 
 const char kOnInstalledEvent[] = "experimental.runtime.onInstalled";
 const char kNoBackgroundPageError[] = "You do not have a background page.";
+const char kPageLoadError[] = "Background page failed to load.";
 
 }
 
@@ -56,8 +57,13 @@ bool RuntimeGetBackgroundPageFunction::RunImpl() {
   return true;
 }
 
-void RuntimeGetBackgroundPageFunction::OnPageLoaded(ExtensionHost*) {
-  SendResponse(true);
+void RuntimeGetBackgroundPageFunction::OnPageLoaded(ExtensionHost* host) {
+  if (host) {
+    SendResponse(true);
+  } else {
+    error_ = kPageLoadError;
+    SendResponse(false);
+  }
 }
 
 }   // namespace extensions