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

content/browser/mojo/mojo_shell_client_host.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/strings/stringprintf.h"
 #include "base/thread_task_runner_handle.h"
 #include "content/browser/mojo/mojo_shell_client_host.h"
 #include "content/common/mojo/mojo_messages.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/common/mojo_shell_connection.h"
 #include "ipc/ipc_sender.h"
 #include "mojo/application/public/cpp/application_impl.h"
 #include "mojo/converters/network/network_type_converters.h"
 #include "mojo/shell/application_manager.mojom.h"
 #include "third_party/mojo/src/mojo/edk/embedder/embedder.h"
 #include "third_party/mojo/src/mojo/edk/embedder/platform_channel_pair.h"
 #include "third_party/mojo/src/mojo/edk/embedder/scoped_platform_handle.h"
 
 namespace content {
 namespace {
 
 const char kMojoShellInstanceURL[] = "mojo_shell_instance_url";
+const char kMojoPlatformFile[] = "mojo_platform_file";
 
 void DidCreateChannel(mojo::embedder::ChannelInfo* info) {}
 
 base::PlatformFile PlatformFileFromScopedPlatformHandle(
     mojo::embedder::ScopedPlatformHandle handle) {
 #if defined(OS_POSIX)
   return handle.release().fd;
 #elif defined(OS_WIN)
   return handle.release().handle;
 #endif
 }
 
 class InstanceURL : public base::SupportsUserData::Data {
  public:
   InstanceURL(const std::string& instance_url) : instance_url_(instance_url) {}
   ~InstanceURL() override {}
 
   std::string get() const { return instance_url_; }
 
  private:
   std::string instance_url_;
 
   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())
     return;
 
   // Create the channel to be shared with the target process.
   mojo::embedder::HandlePassingInformation handle_passing_info;
   mojo::embedder::PlatformChannelPair platform_channel_pair;
 
   // Give one end to the shell so that it can create an instance.
@@ skipping 13 matching lines @@
   //             chokepoint for all process types) and how to wire it through.
   //             http://crbug.com/555393
   std::string url =
       base::StringPrintf("exe:chrome_renderer%d", child_process_id);
   application_manager->CreateInstanceForHandle(
       mojo::ScopedHandle(mojo::Handle(handle.release().value())), url);
 
   // 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);
 
   // Store the URL on the RPH so client code can access it later via
   // GetMojoApplicationInstanceURL().
   SetMojoApplicationInstanceURL(render_process_host, url);
 }
 
 std::string GetMojoApplicationInstanceURL(
     RenderProcessHost* render_process_host) {
   InstanceURL* instance_url = static_cast<InstanceURL*>(
       render_process_host->GetUserData(kMojoShellInstanceURL));
   return instance_url ? instance_url->get() : std::string();
 }
 
+void SendExternalMojoShellHandleToChild(
+    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