Change the Webview gRPC service handler to take in the service and CQ

Rather than start a new service, allow the caller to re-use an existing
connection. In this model, the caller is responsible for initializing
the service and a completion queue the async Webview service would be
using to execute tasks.

BUG=b/132811925
TEST=Compiled

Change-Id: I7e7cdffdccc6f9e7282a1b952e2e5d8013a93be3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1804556
Commit-Queue: Daniel Nicoara <dnicoara@chromium.org>
Reviewed-by: Alex Sakhartchouk <alexst@chromium.org>
Cr-Commit-Position: refs/heads/master@{#696890}

chromecast/browser/webview/webview_grpc_service.cc

@@ -233,28 +233,17 @@ void WebviewRpcInstance::OnError(const std::string& error_message) {
 }  // namespace
 
 WebviewAsyncService::WebviewAsyncService(
-    scoped_refptr<base::SingleThreadTaskRunner> webview_task_runner)
-    : webview_task_runner_(std::move(webview_task_runner)) {}
-
-WebviewAsyncService::~WebviewAsyncService() {
-  if (server_) {
-    server_->Shutdown();
-    cq_->Shutdown();
-
-    base::PlatformThread::Join(rpc_thread_);
-  }
+    std::unique_ptr<webview::WebviewService::AsyncService> service,
+    std::unique_ptr<grpc::ServerCompletionQueue> cq,
+    scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner)
+    : ui_task_runner_(std::move(ui_task_runner)),
+      cq_(std::move(cq)),
+      service_(std::move(service)) {
+  base::PlatformThread::Create(0, this, &rpc_thread_);
 }
 
-void WebviewAsyncService::StartWithSocket(const base::FilePath& socket_path) {
-  DCHECK(!server_.get());
-
-  grpc::ServerBuilder builder;
-  builder.AddListeningPort("unix:" + socket_path.value(),
-                           grpc::InsecureServerCredentials());
-  builder.RegisterService(&service_);
-  cq_ = builder.AddCompletionQueue();
-  server_ = builder.BuildAndStart();
-  base::PlatformThread::Create(0, this, &rpc_thread_);
+WebviewAsyncService::~WebviewAsyncService() {
+  base::PlatformThread::Join(rpc_thread_);
 }
 
 void WebviewAsyncService::ThreadMain() {
@@ -263,7 +252,7 @@ void WebviewAsyncService::ThreadMain() {
   void* tag;
   bool ok;
   // This self-deletes.
-  new WebviewRpcInstance(&service_, cq_.get(), webview_task_runner_);
+  new WebviewRpcInstance(service_.get(), cq_.get(), ui_task_runner_);
   // This thread is joined when this service is destroyed.
   while (cq_->Next(&tag, &ok)) {
     reinterpret_cast<GrpcCallback*>(tag)->Run(ok);

chromecast/browser/webview/webview_grpc_service.h

@@ -19,21 +19,24 @@ namespace chromecast {
 // webviews. See the proto file for commands.
 class WebviewAsyncService : public base::PlatformThread::Delegate {
  public:
-  explicit WebviewAsyncService(
-      scoped_refptr<base::SingleThreadTaskRunner> webview_task_runner);
+  WebviewAsyncService(
+      std::unique_ptr<webview::WebviewService::AsyncService> service,
+      std::unique_ptr<grpc::ServerCompletionQueue> cq,
+      scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner);
   ~WebviewAsyncService() override;
 
-  // Start the server listening on an address, eg "localhost:12345".
-  void StartWithSocket(const base::FilePath& socket_path);
-
  private:
   void ThreadMain() override;
 
+  // Separate thread to run the gRPC completion queue on.
   base::PlatformThreadHandle rpc_thread_;
-  scoped_refptr<base::SingleThreadTaskRunner> webview_task_runner_;
+
+  // Requests need to be posted back to the browser main UI thread to manage
+  // Webview state.
+  scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner_;
+
   std::unique_ptr<grpc::ServerCompletionQueue> cq_;
-  webview::WebviewService::AsyncService service_;
-  std::unique_ptr<grpc::Server> server_;
+  std::unique_ptr<webview::WebviewService::AsyncService> service_;
 
   DISALLOW_COPY_AND_ASSIGN(WebviewAsyncService);
 };