Mojo: Add the ability to notify a Mojo Channel that it's going to be destroyed soon.

* The actual destruction will typically happen on a different thread.
* We'd like to suppress warnings about the OS "pipe" being broken (which
  it often will, because we kill processes rather than shut them down).
* We'd like to know if we're still sending stuff on the channel even
  though it's about to go away.

R=yzshen@chromium.org, sky@chromium.org

Review URL: https://codereview.chromium.org/472603002

Cr-Commit-Position: refs/heads/master@{#289531}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@289531 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 11 insertions, 2 deletions

diff --git a/content/browser/mojo/mojo_application_host.cc b/content/browser/mojo/mojo_application_host.cc
index 2491252..3af7974 100644
--- a/content/browser/mojo/mojo_application_host.cc
+++ b/content/browser/mojo/mojo_application_host.cc
@@ -59,4 +59,8 @@ bool MojoApplicationHost::Activate(IPC::Sender* sender,
   return did_activate_;
 }
 
+void MojoApplicationHost::WillDestroySoon() {
+  channel_init_.WillDestroySoon();
+}
+
 }  // namespace content
diff --git a/content/browser/mojo/mojo_application_host.h b/content/browser/mojo/mojo_application_host.h
index ae57104..27a43f8 100644
--- a/content/browser/mojo/mojo_application_host.h
+++ b/content/browser/mojo/mojo_application_host.h
@@ -32,6 +32,8 @@ class MojoApplicationHost {
   bool Init();
   bool Activate(IPC::Sender* sender, base::ProcessHandle process_handle);
 
+  void WillDestroySoon();
+
   bool did_activate() const { return did_activate_; }
 
   ServiceRegistry* service_registry() { return &service_registry_; }
diff --git a/content/browser/renderer_host/render_process_host_impl.cc b/content/browser/renderer_host/render_process_host_impl.cc
index 5da8d51..399244e 100644
--- a/content/browser/renderer_host/render_process_host_impl.cc
+++ b/content/browser/renderer_host/render_process_host_impl.cc
@@ -923,8 +923,7 @@ void RenderProcessHostImpl::NotifyTimezoneChange() {
 }
 
 ServiceRegistry* RenderProcessHostImpl::GetServiceRegistry() {
-  if (!mojo_application_host_)
-    return NULL;
+  DCHECK(mojo_application_host_);
   return mojo_application_host_->service_registry();
 }
 
@@ -1922,6 +1921,8 @@ void RenderProcessHostImpl::ProcessDied(bool already_dead) {
                     RenderProcessExited(this, GetHandle(), status, exit_code));
   within_process_died_observer_ = false;
 
+  mojo_application_host_->WillDestroySoon();
+
   child_process_launcher_.reset();
   channel_.reset();
   gpu_message_filter_ = NULL;
@@ -2024,6 +2025,8 @@ void RenderProcessHostImpl::OnShutdownRequest() {
       Source<RenderProcessHost>(this),
       NotificationService::NoDetails());
 
+  mojo_application_host_->WillDestroySoon();
+
   Send(new ChildProcessMsg_Shutdown());
 }