[fuchsia] Only create a single channel for ApplicationContext

A channel for chromium.cast.ApplicationContext was created in both
PendingCastComponent and CastComponent. This sometimes caused issues
in agents that make use of ScopedServiceBinding to handle the
server-end of this channel. These agents could get into a state where
they never got a signal on the second client disconnect.

Bug: 1095217, b/158684780
Change-Id: I06e8e1dd35516bb88ea4929e9f43fb4cd862cd1a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2246794
Commit-Queue: Fabrice de Gans-Riberi <fdegans@chromium.org>
Reviewed-by: Kevin Marshall <kmarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#778597}

fuchsia/runners/cast/cast_component.cc

@@ -57,6 +57,7 @@ CastComponent::CastComponent(WebContentRunner* runner,
       initial_url_rewrite_rules_(
           std::move(params.initial_url_rewrite_rules.value())),
       api_bindings_client_(std::move(params.api_bindings_client)),
+      application_context_(params.application_context.Bind()),
       media_session_id_(params.media_session_id.value()),
       headless_disconnect_watch_(FROM_HERE) {
   base::AutoReset<bool> constructor_active_reset(&constructor_active_, true);
@@ -132,9 +133,6 @@ void CastComponent::StartComponent() {
         application_config_.force_content_dimensions()));
   }
 
-  application_context_ =
-      agent_manager_->ConnectToAgentService<chromium::cast::ApplicationContext>(
-          application_config_.agent_url());
   application_controller_ = std::make_unique<ApplicationControllerImpl>(
       frame(), application_context_.get());
 

fuchsia/runners/cast/cast_component.h

@@ -52,6 +52,8 @@ class CastComponent : public WebComponent,
     // Parameters asynchronously initialized by PendingCastComponent.
     std::unique_ptr<ApiBindingsClient> api_bindings_client;
     chromium::cast::ApplicationConfig application_config;
+    fidl::InterfaceHandle<chromium::cast::ApplicationContext>
+        application_context;
     base::Optional<std::vector<fuchsia::web::UrlRequestRewriteRule>>
         initial_url_rewrite_rules;
     base::Optional<uint64_t> media_session_id;

fuchsia/runners/cast/pending_cast_component.cc

@@ -163,5 +163,7 @@ void PendingCastComponent::MaybeLaunchComponent() {
   // user-after-free of |this|.
   params_.url_rewrite_rules_provider.set_error_handler(nullptr);
 
+  params_.application_context = application_context_.Unbind();
+
   delegate_->LaunchPendingComponent(this, std::move(params_));
 }