RemoteMacViews: Add AppShimHostBootstrap::GetAppShimPid

This will be queried in ExtensionAppShimHandler::OnProfileLoaded, where
we will check that the pid's signature.

Bug: 913362
Change-Id: I6fd144b26fad182d040f302f078a343cd2ab6cd9
Reviewed-on: https://chromium-review.googlesource.com/c/1373433
Commit-Queue: ccameron <ccameron@chromium.org>
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#615930}

chrome/browser/apps/app_shim/app_shim_host_bootstrap_mac.cc

@@ -4,6 +4,9 @@
 
 #include "chrome/browser/apps/app_shim/app_shim_host_bootstrap_mac.h"
 
+#include <sys/socket.h>
+#include <sys/un.h>
+
 #include <memory>
 #include <utility>
 
@@ -28,6 +31,15 @@ AppShimHostBootstrap::~AppShimHostBootstrap() {
 void AppShimHostBootstrap::ServeChannel(
     mojo::PlatformChannelEndpoint endpoint) {
   DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+
+  DCHECK(endpoint.platform_handle().is_fd());
+  socklen_t pid_size = sizeof(pid_);
+  if (getsockopt(endpoint.platform_handle().GetFD().get(), SOL_LOCAL,
+                 LOCAL_PEERPID, &pid_, &pid_size)) {
+    LOG(ERROR) << "Failed to get peer pid for app shim.";
+    return;
+  }
+
   mojo::ScopedMessagePipeHandle message_pipe =
       bootstrap_mojo_connection_.Connect(std::move(endpoint));
   host_bootstrap_binding_.Bind(

chrome/browser/apps/app_shim/app_shim_host_bootstrap_mac.h

@@ -10,6 +10,7 @@
 
 #include "base/files/file_path.h"
 #include "base/macros.h"
+#include "base/process/process_handle.h"
 #include "base/threading/thread_checker.h"
 #include "chrome/browser/apps/app_shim/app_shim_host_mac.h"
 #include "chrome/common/mac/app_shim.mojom.h"
@@ -29,6 +30,7 @@ class AppShimHostBootstrap : public chrome::mojom::AppShimHostBootstrap {
   void OnLaunchAppFailed(apps::AppShimLaunchResult result);
 
   chrome::mojom::AppShimHostRequest GetLaunchAppShimHostRequest();
+  base::ProcessId GetAppShimPid() const { return pid_; }
   const std::string& GetAppId() const { return app_id_; }
   const base::FilePath& GetProfilePath() const { return profile_path_; }
 
@@ -59,6 +61,7 @@ class AppShimHostBootstrap : public chrome::mojom::AppShimHostBootstrap {
   // The arguments from the LaunchApp call, and whether or not it has happened
   // yet.
   bool has_received_launch_app_ = false;
+  base::ProcessId pid_ = 0;
   chrome::mojom::AppShimHostRequest app_shim_host_request_;
   base::FilePath profile_path_;
   std::string app_id_;