Convert network hints to Mojo

chromecast/browser/cast_content_browser_client.cc

Index: chromecast/browser/cast_content_browser_client.cc
diff --git a/chromecast/browser/cast_content_browser_client.cc b/chromecast/browser/cast_content_browser_client.cc
index b64ca12915b163b5db7da0f5981cb83d04a01154..7937a4c0ea1dcf6f5012234157e2a050836f475c 100644
--- a/chromecast/browser/cast_content_browser_client.cc
+++ b/chromecast/browser/cast_content_browser_client.cc
@@ -38,7 +38,7 @@
 #include "chromecast/public/media/media_pipeline_backend.h"
 #include "components/crash/content/app/breakpad_linux.h"
 #include "components/crash/content/browser/crash_handler_host_linux.h"
-#include "components/network_hints/browser/network_hints_message_filter.h"
+#include "components/network_hints/browser/network_hints_impl.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/certificate_request_result_type.h"
 #include "content/public/browser/client_certificate_delegate.h"
@@ -52,6 +52,7 @@
 #include "content/public/common/web_preferences.h"
 #include "net/ssl/ssl_cert_request_info.h"
 #include "net/url_request/url_request_context_getter.h"
+#include "services/shell/public/cpp/interface_registry.h"
 #include "ui/display/display.h"
 #include "ui/display/screen.h"
 #include "ui/gl/gl_switches.h"
@@ -209,15 +210,16 @@ void CastContentBrowserClient::RenderProcessWillLaunch(
   // getting HostResolver.
   content::BrowserThread::PostTaskAndReplyWithResult(
       content::BrowserThread::IO, FROM_HERE,
-      base::Bind(&net::URLRequestContextGetter::GetURLRequestContext,
-                 base::Unretained(
-                    url_request_context_factory_->GetSystemGetter())),
-      base::Bind(&CastContentBrowserClient::AddNetworkHintsMessageFilter,
+      base::Bind(
+          &net::URLRequestContextGetter::GetURLRequestContext,
+          base::Unretained(url_request_context_factory_->GetSystemGetter())),
+      base::Bind(&CastContentBrowserClient::AddNetworkHintsImpl,
                  base::Unretained(this), host->GetID()));
 }
 
-void CastContentBrowserClient::AddNetworkHintsMessageFilter(
-    int render_process_id, net::URLRequestContext* context) {
+void CastContentBrowserClient::AddNetworkHintsImpl(
+    int render_process_id,
+    net::URLRequestContext* context) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
 
   content::RenderProcessHost* host =
@@ -225,10 +227,13 @@ void CastContentBrowserClient::AddNetworkHintsMessageFilter(
   if (!host)
     return;
 
-  scoped_refptr<content::BrowserMessageFilter> network_hints_message_filter(
-      new network_hints::NetworkHintsMessageFilter(
-          url_request_context_factory_->host_resolver()));
-  host->AddFilter(network_hints_message_filter.get());
+  network_hints_.reset(new network_hints::NetworkHintsImpl(
+      url_request_context_factory_->host_resolver()));
+  host->GetInterfaceRegistry()->AddInterface(
+      base::Bind(&network_hints::NetworkHintsImpl::Bind,
+                 base::Unretained(network_hints_.get())),

[dcheng, 2016/07/20 13:59:50]

This needs to describe why unretained is safe; better yet, we should figure out
a way not to need Unretained.

[tibell, 2016/07/21 00:12:07]

Added a comment.

I don't think we're going to get away from the Unretained unless the registry
owns the impl. From the discussion on chromium-mojo@ that seems to not be
preferred at the moment.

I do have a CL that has the host able to own impls (similar to how they own
message filters today): https://codereview.chromium.org/2072613003/ This doesn't
get rid of the Unretained, but puts it in one place. If that CL is accepted I
will convert this code to use it.

[dcheng, 2016/07/21 02:43:13]

Long-term, I think it's still a direction we should consider exploring.
Move-only callbacks are going to be coming to Chromium; it's just a matter of
when. At that point, we can guarantee that the registry has ownership of the
callbacks and we can control the deletion semantics fully.

[tibell, 2016/07/21 05:09:45]

I think it might be the right direction as well. See if you can convince
rockot@. :)

+      content::BrowserThread::GetTaskRunnerForThread(
+          content::BrowserThread::IO));
 }
 
 bool CastContentBrowserClient::IsHandledURL(const GURL& url) {