Add support to ExternalMojoBroker for more use cases.

1. Broker to take path in constructor.
2. Broker to create local InterfacePtr for ExternalConnector.

These changes support testing external mojo interfaces outside of
service manager, and with multiple instances.

Bug: internal 138940183
Test: Verified while testing external service.
Change-Id: I367495003c63daf5b1c701af343d8e8871646b18
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1737041Reviewed-by: Kenneth MacKay <kmackay@chromium.org>
Commit-Queue: Chris Letnick <cletnick@google.com>
Auto-Submit: Chris Letnick <cletnick@google.com>
Cr-Commit-Position: refs/heads/master@{#684229}

chromecast/external_mojo/broker_service/BUILD.gn

@@ -9,6 +9,7 @@ source_set("broker_service") {
   ]
   deps = [
     "//base",
+    "//chromecast/external_mojo/public/cpp:common",
     "//chromecast/external_mojo/public/cpp:external_mojo_broker",
     "//services/service_manager/public/cpp",
     "//services/service_manager/public/mojom",

chromecast/external_mojo/broker_service/broker_service.cc

@@ -14,6 +14,7 @@
 #include "base/no_destructor.h"
 #include "base/sequenced_task_runner.h"
 #include "base/threading/thread.h"
+#include "chromecast/external_mojo/public/cpp/common.h"
 #include "chromecast/external_mojo/public/cpp/external_mojo_broker.h"
 #include "services/service_manager/public/cpp/manifest_builder.h"
 
@@ -68,7 +69,8 @@ BrokerService::BrokerService(service_manager::mojom::ServiceRequest request)
   for (const auto& sub_manifest : manifest.packaged_services) {
     external_services_to_proxy.push_back(sub_manifest.service_name);
   }
-  broker_ = base::SequenceBound<ExternalMojoBroker>(io_thread_->task_runner());
+  broker_ = base::SequenceBound<ExternalMojoBroker>(io_thread_->task_runner(),
+                                                    GetBrokerPath());
   broker_.Post(FROM_HERE, &ExternalMojoBroker::InitializeChromium,
                service_binding_.GetConnector()->Clone(),
                external_services_to_proxy);

chromecast/external_mojo/external_service_support/BUILD.gn

@@ -70,6 +70,7 @@ executable("standalone_mojo_broker") {
   deps = [
     ":process_setup",
     "//base",
+    "//chromecast/external_mojo/public/cpp:common",
     "//chromecast/external_mojo/public/cpp:external_mojo_broker",
     "//mojo/core/embedder",
   ]

chromecast/external_mojo/external_service_support/standalone_mojo_broker.cc

@@ -11,6 +11,7 @@
 #include "base/run_loop.h"
 #include "base/task/single_thread_task_executor.h"
 #include "chromecast/external_mojo/external_service_support/process_setup.h"
+#include "chromecast/external_mojo/public/cpp/common.h"
 #include "chromecast/external_mojo/public/cpp/external_mojo_broker.h"
 #include "mojo/core/embedder/embedder.h"
 #include "mojo/core/embedder/scoped_ipc_support.h"
@@ -32,7 +33,8 @@ int main(int argc, char** argv) {
       io_task_executor.task_runner(),
       mojo::core::ScopedIPCSupport::ShutdownPolicy::CLEAN);
 
-  chromecast::external_mojo::ExternalMojoBroker broker;
+  chromecast::external_mojo::ExternalMojoBroker broker(
+      chromecast::external_mojo::GetBrokerPath());
 
   run_loop.Run();
 

chromecast/external_mojo/public/cpp/external_mojo_broker.cc

@@ -375,11 +375,13 @@ class ExternalMojoBroker::ReadWatcher
   DISALLOW_COPY_AND_ASSIGN(ReadWatcher);
 };
 
-ExternalMojoBroker::ExternalMojoBroker() {
+ExternalMojoBroker::ExternalMojoBroker(const std::string& broker_path) {
   connector_ = std::make_unique<ConnectorImpl>();
 
+  LOG(INFO) << "Initializing external mojo broker at: " << broker_path;
+
   mojo::NamedPlatformChannel::Options channel_options;
-  channel_options.server_name = GetBrokerPath();
+  channel_options.server_name = broker_path;
   mojo::NamedPlatformChannel named_channel(channel_options);
 
   mojo::PlatformChannelServerEndpoint server_endpoint =
@@ -396,6 +398,12 @@ void ExternalMojoBroker::InitializeChromium(
                                  external_services_to_proxy);
 }
 
+mojom::ExternalConnectorPtr ExternalMojoBroker::CreateConnector() {
+  mojom::ExternalConnectorPtrInfo info;
+  connector_->AddBinding(mojo::MakeRequest(&info));
+  return mojom::ExternalConnectorPtr(std::move(info));
+}
+
 ExternalMojoBroker::~ExternalMojoBroker() = default;
 
 }  // namespace external_mojo

chromecast/external_mojo/public/cpp/external_mojo_broker.h

@@ -10,6 +10,7 @@
 #include <vector>
 
 #include "base/macros.h"
+#include "chromecast/external_mojo/public/mojom/connector.mojom.h"
 
 namespace service_manager {
 class Connector;
@@ -22,7 +23,8 @@ namespace external_mojo {
 // either in a standalone broker process, or embedded into a Chromium process.
 class ExternalMojoBroker {
  public:
-  ExternalMojoBroker();
+  explicit ExternalMojoBroker(const std::string& broker_path);
+
   ~ExternalMojoBroker();
 
   // Initializes the embedded into a Chromium process (eg in cast_shell).
@@ -33,6 +35,8 @@ class ExternalMojoBroker {
       std::unique_ptr<service_manager::Connector> connector,
       const std::vector<std::string>& external_services_to_proxy);
 
+  mojom::ExternalConnectorPtr CreateConnector();
+
  private:
   class ConnectorImpl;
   class ReadWatcher;