libdrm-dev is now a required package on GCE instances

compute_engine_scripts/chromecompute/vm_create_setup_instances.sh

 #!/bin/bash
 #
 # Create and setup the Skia RecreateSKPs GCE instance.
 #
 # Copyright 2014 Google Inc. All Rights Reserved.
 # Author: rmistry@google.com (Ravi Mistry)
 
 source vm_config.sh
 source vm_setup_utils.sh
 
 # Set OS specific GCE variables.
 if [ "$VM_INSTANCE_OS" == "Linux" ]; then
   SKIA_BOT_IMAGE_NAME=$SKIA_BOT_LINUX_IMAGE_NAME
   REQUIRED_FILES_FOR_BOTS=${REQUIRED_FILES_FOR_LINUX_BOTS[@]}
-  WAIT_TIME_AFTER_CREATION_SECS=240
+  WAIT_TIME_AFTER_CREATION_SECS=600
 elif [ "$VM_INSTANCE_OS" == "Windows" ]; then
   SKIA_BOT_IMAGE_NAME=$SKIA_BOT_WIN_IMAGE_NAME
   ZONE=$WINDOWS_ZONE
 
   ORIG_STARTUP_SCRIPT="../../scripts/win_setup.ps1"
   MODIFIED_STARTUP_SCRIPT="/tmp/win_setup.ps1"
   # Set chrome-bot's password in win_setup.ps1
   cp $ORIG_STARTUP_SCRIPT $MODIFIED_STARTUP_SCRIPT
   sed -i "s/CHROME_BOT_PASSWORD/$(echo $(cat /tmp/gce.txt) | sed -e 's/[\/&]/\\&/g')/g" $MODIFIED_STARTUP_SCRIPT
   sed -i "s/GS_ACCESS_KEY_ID/$(echo $(cat ~/.boto | sed -n 2p) | sed -e 's/[\/&]/\\&/g')/g" $MODIFIED_STARTUP_SCRIPT
@@ skipping 93 matching lines @@
     # Restart the windows instance to run chrome-bot's scheduled task.
     $GCOMPUTE_CMD resetinstance $INSTANCE_NAME
   fi
 done
 
 cat <<INP
 
 Instances are ready to use.
 
 INP