Add a ServiceRegistry::ConnectToRemoteService that takes an InterfaceRequest<>.

And change the task manager to use it.

Review URL: https://codereview.chromium.org/1137803005

Cr-Commit-Position: refs/heads/master@{#330881}

chrome/browser/process_resource_usage.h

@@ -22,13 +22,31 @@
 // about://memory-internals.
 //
 // To create:
-// 1. Obtain a ResourceUsageReporter connection using the child process's
-//    service registry. i.e:
-//    ResourceUsageReporterPtr service;
-//    process->GetServiceRegistry()->ConnectToRemoteService(&service);
-// 2. If needed, the connection can be passed to another thread using
-//    ResourceUsageReporterPtr::PassInterface().
-// 3. Pass the service to the constructor.
+// 1. Create a ResourceUsageReporterPtr and obtain an InterfaceRequest<> using
+//    mojo::GetProxy.
+// 2. Use the child process's service registry to connect to the service using
+//    the InterfaceRequest<>. Note, ServiceRegistry is thread hostile and
+//    must always be accessed from the same thread. However, InterfaceRequest<>
+//    can be passed safely between threads, and therefore a task can be posted
+//    to the ServiceRegistry thread to connect to the remote service.
+// 3. Pass the ResourceUsageReporterPtr to the constructor.
+//
+// Example:
+//   void Foo::ConnectToService(
+//       mojo::InterfaceRequest<ResourceUsageReporter> req) {
+//     content::ServiceRegistry* registry = host_->GetServiceRegistry();
+//     registry->ConnectToRemoteService(req.Pass());
+//   }
+//
+//   ...
+//     ResourceUsageReporterPtr service;
+//     mojo::InterfaceRequest<ResourceUsageReporter> request =
+//         mojo::GetProxy(&service);
+//     content::BrowserThread::PostTask(
+//         content::BrowserThread::IO, FROM_HERE,
+//         base::Bind(&Foo::ConnectToService, this, base::Passed(&request)));
+//     resource_usage_.reset(new ProcessResourceUsage(service.Pass()));
+//   ...
 //
 // Note: ProcessResourceUsage is thread-hostile and must live on a single
 // thread.

chrome/browser/task_manager/child_process_resource_provider.cc

@@ -60,11 +60,8 @@ class ChildProcessResource : public Resource {
   // process would be "Plugin: Flash" when name is "Flash".
   base::string16 GetLocalizedTitle() const;
 
-  static mojo::InterfacePtrInfo<ResourceUsageReporter>
-  GetProcessUsageOnIOThread(int id);
-
-  void OnGetProcessUsageDone(
-      mojo::InterfacePtrInfo<ResourceUsageReporter> info);
+  static void ConnectResourceReporterOnIOThread(
+      int id, mojo::InterfaceRequest<ResourceUsageReporter> req);
 
   int process_type_;
   base::string16 name_;
@@ -88,21 +85,19 @@ class ChildProcessResource : public Resource {
 gfx::ImageSkia* ChildProcessResource::default_icon_ = NULL;
 
 // static
-mojo::InterfacePtrInfo<ResourceUsageReporter>
-ChildProcessResource::GetProcessUsageOnIOThread(int id) {
+void ChildProcessResource::ConnectResourceReporterOnIOThread(
+    int id, mojo::InterfaceRequest<ResourceUsageReporter> req) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   content::BrowserChildProcessHost* host =
       content::BrowserChildProcessHost::FromID(id);
   if (!host)
-    return mojo::InterfacePtrInfo<ResourceUsageReporter>();
+    return;
 
   content::ServiceRegistry* registry = host->GetServiceRegistry();
   if (!registry)
-    return mojo::InterfacePtrInfo<ResourceUsageReporter>();
+    return;
 
-  ResourceUsageReporterPtr service;
-  registry->ConnectToRemoteService(&service);
-  return service.PassInterface().Pass();
+  registry->ConnectToRemoteService(req.Pass());
 }
 
 ChildProcessResource::ChildProcessResource(int process_type,
@@ -123,27 +118,19 @@ ChildProcessResource::ChildProcessResource(int process_type,
     default_icon_ = rb.GetImageSkiaNamed(IDR_PLUGINS_FAVICON);
     // TODO(jabdelmalek): use different icon for web workers.
   }
-  BrowserThread::PostTaskAndReplyWithResult(
+  ResourceUsageReporterPtr service;
+  mojo::InterfaceRequest<ResourceUsageReporter> request =
+      mojo::GetProxy(&service);
+  BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
-      base::Bind(&ChildProcessResource::GetProcessUsageOnIOThread,
-                 unique_process_id),
-      base::Bind(&ChildProcessResource::OnGetProcessUsageDone,
-                 weak_factory_.GetWeakPtr()));
+      base::Bind(&ChildProcessResource::ConnectResourceReporterOnIOThread,
+                 unique_process_id, base::Passed(&request)));
+  resource_usage_.reset(new ProcessResourceUsage(service.Pass()));
 }
 
 ChildProcessResource::~ChildProcessResource() {
 }
 
-void ChildProcessResource::OnGetProcessUsageDone(
-    mojo::InterfacePtrInfo<ResourceUsageReporter> info) {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  if (info.is_valid()) {
-    ResourceUsageReporterPtr service;
-    service.Bind(info.Pass());
-    resource_usage_.reset(new ProcessResourceUsage(service.Pass()));
-  }
-}
-
 // Resource methods:
 base::string16 ChildProcessResource::GetTitle() const {
   if (title_.empty())

content/public/common/service_registry.h

@@ -54,8 +54,11 @@ class CONTENT_EXPORT ServiceRegistry {
   // Connect to an interface provided by the remote service provider.
   template <typename Interface>
   void ConnectToRemoteService(mojo::InterfacePtr<Interface>* ptr) {
-    ConnectToRemoteService(Interface::Name_,
-                           mojo::GetProxy(ptr).PassMessagePipe());
+    ConnectToRemoteService(mojo::GetProxy(ptr));
+  }
+  template <typename Interface>
+  void ConnectToRemoteService(mojo::InterfaceRequest<Interface> ptr) {
+    ConnectToRemoteService(Interface::Name_, ptr.PassMessagePipe());
   }
   virtual void ConnectToRemoteService(const base::StringPiece& name,
                                       mojo::ScopedMessagePipeHandle handle) = 0;