Track last active terminal in TerminalPrivateAPI and use for vsh

Keep track of the last active terminal by capturing terminal_id
sent from the web app.  When a new process is opened, we call
cicerone GetVshSession to find the container shell pid to set for cwd.

Bug: 1113207
Change-Id: Ia6ff0eb43b9bcefa781f19d141b36143cfd48649
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2351644Reviewed-by: Jason Lin <lxj@google.com>
Commit-Queue: Joel Hockey <joelhockey@chromium.org>
Cr-Commit-Position: refs/heads/master@{#799003}

chrome/browser/extensions/api/terminal/terminal_private_api.h

@@ -59,27 +59,38 @@ class TerminalPrivateOpenTerminalProcessFunction : public ExtensionFunction {
       std::unique_ptr<std::vector<std::string>> args);
 
  private:
-  // Callback for when starting crostini is complete.
   void OnCrostiniRestarted(
       std::unique_ptr<CrostiniStartupStatus> startup_status,
       const std::string& user_id_hash,
       int tab_id,
-      const std::vector<std::string>& arguments,
+      base::CommandLine cmdline,
       crostini::CrostiniResult result);
 
+  void OpenVmshellProcess(const std::string& user_id_hash,
+                          int tab_id,
+                          base::CommandLine cmdline);
+
+  void OnGetVshSession(const std::string& user_id_hash,
+                       int tab_id,
+                       base::CommandLine cmdline,
+                       int32_t vsh_pid,
+                       bool success,
+                       const std::string& failure_reason,
+                       int32_t container_shell_pid);
+
+  void OpenProcess(const std::string& user_id_hash,
+                   int tab_id,
+                   base::CommandLine cmdline);
+
   using ProcessOutputCallback =
       base::Callback<void(const std::string& terminal_id,
                           const std::string& output_type,
                           const std::string& output)>;
   using OpenProcessCallback =
       base::Callback<void(bool success, const std::string& terminal_id)>;
-
-  void OpenProcess(const std::string& user_id_hash,
-                   int tab_id,
-                   const std::vector<std::string>& arguments);
   void OpenOnRegistryTaskRunner(const ProcessOutputCallback& output_callback,
                                 const OpenProcessCallback& callback,
-                                const std::vector<std::string>& arguments,
+                                base::CommandLine cmdline,
                                 const std::string& user_id_hash);
   void RespondOnUIThread(bool success, const std::string& terminal_id);
 };