[Android] Fix gn build for instrumentation tests.

tools/android/forwarder2/host_forwarder_main.cc

 // Copyright (c) 2012 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 <errno.h>
 #include <signal.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <unistd.h>
 
@@ skipping 31 matching lines @@
 #include "tools/android/forwarder2/pipe_notifier.h"
 #include "tools/android/forwarder2/socket.h"
 #include "tools/android/forwarder2/util.h"
 
 namespace forwarder2 {
 namespace {
 
 const char kLogFilePath[] = "/tmp/host_forwarder_log";
 const char kDaemonIdentifier[] = "chrome_host_forwarder_daemon";
 
-const char kKillServerCommand[] = "kill-server";
-const char kForwardCommand[] = "forward";
-
 const int kBufSize = 256;
 
 // Needs to be global to be able to be accessed from the signal handler.
 PipeNotifier* g_notifier = NULL;
 
 // Lets the daemon fetch the exit notifier file descriptor.
 int GetExitNotifierFD() {
   DCHECK(g_notifier);
   return g_notifier->receiver_fd();
 }
@@ skipping 292 matching lines @@
   ClientDelegate(const Pickle& command_pickle)
       : command_pickle_(command_pickle),
         has_failed_(false) {
   }
 
   bool has_failed() const { return has_failed_; }
 
   // Daemon::ClientDelegate:
   virtual void OnDaemonReady(Socket* daemon_socket) override {
     // Send the forward command to the daemon.
-    CHECK_EQ(command_pickle_.size(),
+    CHECK_EQ(static_cast<long>(command_pickle_.size()),
              daemon_socket->WriteNumBytes(command_pickle_.data(),
                                           command_pickle_.size()));
     char buf[kBufSize];
     const int bytes_read = daemon_socket->Read(
         buf, sizeof(buf) - 1 /* leave space for null terminator */);
     CHECK_GT(bytes_read, 0);
-    DCHECK(bytes_read < sizeof(buf));
+    DCHECK(static_cast<size_t>(bytes_read) < sizeof(buf));
     buf[bytes_read] = 0;
     base::StringPiece msg(buf, bytes_read);
     if (msg.starts_with("ERROR")) {
       LOG(ERROR) << msg;
       has_failed_ = true;
       return;
     }
     printf("%s\n", buf);
   }
 
@@ skipping 66 matching lines @@
 
   return client_delegate.has_failed() || daemon_delegate.has_failed();
 }
 
 }  // namespace
 }  // namespace forwarder2
 
 int main(int argc, char** argv) {
   return forwarder2::RunHostForwarder(argc, argv);
 }