Allow mojo_runner to connect to arbitrary executables.

mojo/runner/child_process_host.cc

 // Copyright 2014 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 "mojo/runner/child_process_host.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/location.h"
 #include "base/logging.h"
@@ skipping 85 matching lines @@
 
   if (!child_process_.IsValid()) {
     LOG(ERROR) << "Failed to start child process";
     AppCompleted(MOJO_RESULT_UNKNOWN);
   }
 }
 
 void ChildProcessHost::DoLaunch() {
   const base::CommandLine* parent_command_line =
       base::CommandLine::ForCurrentProcess();
-  base::CommandLine child_command_line(parent_command_line->GetProgram());
+  base::FilePath target_path = parent_command_line->GetProgram();
+  // |app_path_| can be empty in tests.
+  if (!app_path_.MatchesExtension(FILE_PATH_LITERAL(".mojo")) &&
+      !app_path_.empty()) {
+    target_path = app_path_;
+  }
+
+  base::CommandLine child_command_line(target_path);
   child_command_line.AppendArguments(*parent_command_line, false);
-  child_command_line.AppendSwitchPath(switches::kChildProcess, app_path_);
+
+  if (target_path != app_path_)
+    child_command_line.AppendSwitchPath(switches::kChildProcess, app_path_);
 
   if (start_sandboxed_)
     child_command_line.AppendSwitch(switches::kEnableSandbox);
 
   embedder::HandlePassingInformation handle_passing_info;
   platform_channel_pair_.PrepareToPassClientHandleToChildProcess(
       &child_command_line, &handle_passing_info);
 
   base::LaunchOptions options;
 #if defined(OS_WIN)
@@ skipping 34 matching lines @@
 void ChildProcessHost::DidCreateChannel(embedder::ChannelInfo* channel_info) {
   DVLOG(2) << "AppChildProcessHost::DidCreateChannel()";
 
   DCHECK(channel_info ||
          base::CommandLine::ForCurrentProcess()->HasSwitch("use-new-edk"));
   channel_info_ = channel_info;
 }
 
 }  // namespace runner
 }  // namespace mojo