fix(build_library): Remove usb and factory_layout partition layouts.

These are just cluttering things and adding an element of "how does this
work?" because base_image_util was defaulting to the "usb" layout in
some places and "base" in others.

build_library/base_image_util.sh

@@ -40,14 +40,10 @@ create_base_image() {
   local image_name=$1
   local rootfs_verification_enabled=$2
   local bootcache_enabled=$3
-  local image_type="usb"
+  local image_type="base"
 
   if [[ "${FLAGS_disk_layout}" != "default" ]]; then
       image_type="${FLAGS_disk_layout}"
-  else
-    if should_build_image ${CHROMEOS_FACTORY_INSTALL_SHIM_NAME}; then
-      image_type="factory_install"
-    fi
   fi
 
   check_valid_layout "base"

build_library/disk_layout_util.sh

@@ -112,9 +112,6 @@ check_valid_layout() {
 
 get_disk_layout_type() {
   DISK_LAYOUT_TYPE="base"
-  if should_build_image ${CHROMEOS_FACTORY_INSTALL_SHIM_NAME}; then
-    DISK_LAYOUT_TYPE="factory_install"
-  fi
 }
 
 emit_gpt_scripts() {

build_library/legacy_disk_layout.json

@@ -66,52 +66,6 @@
         "blocks":"2097152"
       }
     ],
-    "usb": [
-      {
-        "num": 3,
-        "label":"ROOT-A",
-        "uuid":"7130c94a-213a-4e5a-8e26-6cce9662f132",
-        "type":"coreos-rootfs",
-        "blocks":"2539520",
-        "fs_blocks":"262144"
-      },
-      {
-        "num": 4,
-        "label":"ROOT-B",
-        "uuid":"e03dd35c-7c2d-4a47-b3fe-27f15780a57c",
-        "type":"coreos-rootfs",
-        "blocks":"1"
-      }
-    ],
-    "factory_install": [
-      {
-        "num": 1,
-        "label":"EFI-SYSTEM",
-        "type":"efi",
-        "blocks":"65536"
-      },
-      {
-        "num": 3,
-        "label":"ROOT-A",
-        "uuid":"7130c94a-213a-4e5a-8e26-6cce9662f132",
-        "type":"coreos-rootfs",
-        "blocks":"860160",
-        "fs_blocks":"102400"
-      },
-      {
-        "num": 4,
-        "label":"ROOT-B",
-        "uuid":"e03dd35c-7c2d-4a47-b3fe-27f15780a57c",
-        "type":"coreos-rootfs",
-        "blocks":"1"
-      },
-      {
-        "num": 9,
-        "label":"STATE",
-        "type":"data",
-        "blocks":"286720"
-      }
-    ],
     "vm": [
       {
         "num": 9,