[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..988e5b1b758d9efe06b5ad62853e272a5d7e7e4c 100644
--- a/chrome/browser/extensions/api/dial/device_description_fetcher.cc
+++ b/chrome/browser/extensions/api/dial/device_description_fetcher.cc
@@ -28,24 +28,26 @@ namespace dial {
 
 DeviceDescriptionFetcher::DeviceDescriptionFetcher(
     const GURL& device_description_url,
-    Profile* profile,
+    net::URLRequestContextGetter* request_context,
+    BrowserThread::ID thread_id,
     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),
+      thread_id_(thread_id),
       success_cb_(std::move(success_cb)),
       error_cb_(std::move(error_cb)) {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  DCHECK(profile_);
+  DCHECK_CURRENTLY_ON(thread_id_);
+  DCHECK(request_context_);
   DCHECK(device_description_url_.is_valid());
 }
 
 DeviceDescriptionFetcher::~DeviceDescriptionFetcher() {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  DCHECK_CURRENTLY_ON(thread_id_);
 }
 
 void DeviceDescriptionFetcher::Start() {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  DCHECK_CURRENTLY_ON(thread_id_);

[imcheng, 2017/02/22 03:45:04]

If you are checking that the methods are being called on the same thread as the
one the object is created in, then you can just use a base::ThreadChecker.

https://cs.chromium.org/chromium/src/base/threading/thread_checker.h?q=base::...

[mark a. foltz, 2017/03/01 21:44:00]

+1

[zhaobin, 2017/03/02 07:04:35]

Done.

   DCHECK(!fetcher_);
 
   // DIAL returns device descriptions via GET request.
@@ -70,7 +72,7 @@ void DeviceDescriptionFetcher::Start() {
   fetcher_->SetMaxRetriesOn5xx(kMaxRetries);
   fetcher_->SetAutomaticallyRetryOnNetworkChanges(kMaxRetries);
 
-  fetcher_->SetRequestContext(profile_->GetRequestContext());
+  fetcher_->SetRequestContext(request_context_);
   fetcher_->Start();
 }