[DIAL] Break circular dependency in DialFetchDeviceDescriptionFunction.

chrome/browser/extensions/api/dial/dial_api.cc

Index: chrome/browser/extensions/api/dial/dial_api.cc
diff --git a/chrome/browser/extensions/api/dial/dial_api.cc b/chrome/browser/extensions/api/dial/dial_api.cc
index 6099c0277d891a24400da675b77269a342d7dfe3..783992bf2befac1cd57264254d3728ba5dc9f878 100644
--- a/chrome/browser/extensions/api/dial/dial_api.cc
+++ b/chrome/browser/extensions/api/dial/dial_api.cc
@@ -240,6 +240,9 @@ void DialFetchDeviceDescriptionFunction::MaybeStartFetch(const GURL& url) {
 
 void DialFetchDeviceDescriptionFunction::OnFetchComplete(
     const api::dial::DialDeviceDescriptionData& result) {
+  // Destroy the DeviceDescriptionFetcher since it still contains a reference
+  // to |this| in its un-invoked callback.
+  device_description_fetcher_.reset();
   api::dial::DialDeviceDescription device_description;
   device_description.device_label = params_->device_label;
   device_description.app_url = result.app_url.spec();
@@ -250,6 +253,9 @@ void DialFetchDeviceDescriptionFunction::OnFetchComplete(
 
 void DialFetchDeviceDescriptionFunction::OnFetchError(
     const std::string& message) {
+  // Destroy the DeviceDescriptionFetcher since it still contains a reference
+  // to |this| in its un-invoked callback.
+  device_description_fetcher_.reset();
   SetError(message);
   SendResponse(false);
 }