mustash: Enable connections to mus from the Chrome renderer [take 2]

content/browser/mojo/mojo_shell_client_host.cc

Index: content/browser/mojo/mojo_shell_client_host.cc
diff --git a/content/browser/mojo/mojo_shell_client_host.cc b/content/browser/mojo/mojo_shell_client_host.cc
index 1bc85b51f168de0d8bc05c6909e59fe1d5f3771c..ffafa4b66446cdf896a3caa7e3aa0b262ec038c5 100644
--- a/content/browser/mojo/mojo_shell_client_host.cc
+++ b/content/browser/mojo/mojo_shell_client_host.cc
@@ -20,6 +20,7 @@ namespace content {
 namespace {
 
 const char kMojoShellInstanceURL[] = "mojo_shell_instance_url";
+const char kMojoPlatformFile[] = "mojo_platform_file";
 
 void DidCreateChannel(mojo::embedder::ChannelInfo* info) {}
 
@@ -45,16 +46,35 @@ class InstanceURL : public base::SupportsUserData::Data {
   DISALLOW_COPY_AND_ASSIGN(InstanceURL);
 };
 
+class InstanceShellHandle : public base::SupportsUserData::Data {
+ public:
+  InstanceShellHandle(base::PlatformFile shell_handle)
+      : shell_handle_(shell_handle) {}
+  ~InstanceShellHandle() override {}
+
+  base::PlatformFile get() const { return shell_handle_; }
+
+ private:
+  base::PlatformFile shell_handle_;
+
+  DISALLOW_COPY_AND_ASSIGN(InstanceShellHandle);
+};
+
 void SetMojoApplicationInstanceURL(RenderProcessHost* render_process_host,
                                    const std::string& instance_url) {
   render_process_host->SetUserData(kMojoShellInstanceURL,
                                    new InstanceURL(instance_url));
 }
 
+void SetMojoPlatformFile(RenderProcessHost* render_process_host,
+                         base::PlatformFile platform_file) {
+  render_process_host->SetUserData(kMojoPlatformFile,
+                                   new InstanceShellHandle(platform_file));
+}
+
 }  // namespace
 
 void RegisterChildWithExternalShell(int child_process_id,
-                                    base::ProcessHandle process_handle,
                                     RenderProcessHost* render_process_host) {
   // Some process types get created before the main message loop.
   if (!MojoShellConnection::Get())
@@ -88,8 +108,7 @@ void RegisterChildWithExternalShell(int child_process_id,
   // Send the other end to the child via Chrome IPC.
   base::PlatformFile client_file = PlatformFileFromScopedPlatformHandle(
       platform_channel_pair.PassClientHandle());
-  render_process_host->Send(new MojoMsg_BindExternalMojoShellHandle(
-      IPC::GetFileHandleForProcess(client_file, process_handle, true)));
+  SetMojoPlatformFile(render_process_host, client_file);

[Ben Goodger (Google), 2015/11/25 04:07:28]

Instead of structuring it this way, I'd do this:

- change SetMojoApplicationInstanceURL to just take a RPH
- have it generate & set the url on the RPH
- call it from the RPH ctor

then leave the rest of this function intact.

[Fady Samuel, 2015/11/25 17:45:52]

I think this structuring is necessary. The mojo shell needs to know about the
renderer's URL on ConnectToApplication or else it fails. What I'm doing here is
telling the shell about the renderer, and once the renderer is available, I send
a Chrome IPC message over to tell it how to connect.

 
   // Store the URL on the RPH so client code can access it later via
   // GetMojoApplicationInstanceURL().
@@ -103,4 +122,14 @@ std::string GetMojoApplicationInstanceURL(
   return instance_url ? instance_url->get() : std::string();
 }
 
+void BindExternalMojoShellHandle(base::ProcessHandle process_handle,
+                                 RenderProcessHost* render_process_host) {
+  InstanceShellHandle* client_file = static_cast<InstanceShellHandle*>(
+      render_process_host->GetUserData(kMojoPlatformFile));
+  if (!client_file)
+    return;
+  render_process_host->Send(new MojoMsg_BindExternalMojoShellHandle(
+      IPC::GetFileHandleForProcess(client_file->get(), process_handle, true)));
+}
+
 }  // namespace content