[Dial] Refactor DialRegistry and DeviceDescriptionFetcher so they can be used by MediaSinkService

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

Index: chrome/browser/extensions/api/dial/device_description_fetcher.cc
diff --git a/chrome/browser/extensions/api/dial/device_description_fetcher.cc b/chrome/browser/extensions/api/dial/device_description_fetcher.cc
index 654fc3355c770bd83057e9b61b2abf9cfa3d9fe4..8ee7deeed4d3ef90c930b602ea1d8ef4f06162c8 100644
--- a/chrome/browser/extensions/api/dial/device_description_fetcher.cc
+++ b/chrome/browser/extensions/api/dial/device_description_fetcher.cc
@@ -28,24 +28,25 @@ namespace dial {
 
 DeviceDescriptionFetcher::DeviceDescriptionFetcher(
     const GURL& device_description_url,
-    Profile* profile,
+    net::URLRequestContextGetter* request_context,
+    BrowserThread::ID thread_id,

[imcheng, 2017/03/06 20:56:30]

thread_id can be removed now.

[zhaobin, 2017/03/07 00:13:18]

Done.

     base::OnceCallback<void(const DialDeviceDescriptionData&)> success_cb,
     base::OnceCallback<void(const std::string&)> error_cb)
     : device_description_url_(device_description_url),
-      profile_(profile),
+      request_context_(request_context),
       success_cb_(std::move(success_cb)),
       error_cb_(std::move(error_cb)) {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  DCHECK(profile_);
+  DCHECK(thread_checker_.CalledOnValidThread());

[imcheng, 2017/03/06 20:56:30]

this DCHECK is not necessary since it's just been created.

[zhaobin, 2017/03/07 00:13:18]

Done.

+  DCHECK(request_context_);
   DCHECK(device_description_url_.is_valid());
 }
 
 DeviceDescriptionFetcher::~DeviceDescriptionFetcher() {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  DCHECK(thread_checker_.CalledOnValidThread());
 }
 
 void DeviceDescriptionFetcher::Start() {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(!fetcher_);
 
   // DIAL returns device descriptions via GET request.
@@ -70,7 +71,7 @@ void DeviceDescriptionFetcher::Start() {
   fetcher_->SetMaxRetriesOn5xx(kMaxRetries);
   fetcher_->SetAutomaticallyRetryOnNetworkChanges(kMaxRetries);
 
-  fetcher_->SetRequestContext(profile_->GetRequestContext());
+  fetcher_->SetRequestContext(request_context_);
   fetcher_->Start();
 }