Support unknown Android target devices via environment variables.

platform_tools/android/bin/android_setup.sh

 #!/bin/bash
 #
 # android_setup.sh: Sets environment variables used by other Android scripts.
 
 # Fail-fast if anything in the script fails.
 set -e
 
 BUILDTYPE=${BUILDTYPE-Debug}
 
 while (( "$#" )); do
@@ skipping 116 matching lines @@
     arm_thumb)
       DEFINES="${DEFINES} skia_arch_type=arm arm_neon=0 arm_thumb=1"
       ANDROID_ARCH="arm"
       ;;
     mips)
       DEFINES="${DEFINES} skia_arch_type=mips skia_arch_width=32"
       DEFINES="${DEFINES} skia_resource_cache_mb_limit=32"
       ANDROID_ARCH="mips"
       ;;
     *)
-      echo "ERROR: unknown device $TARGET_DEVICE"
-      exit 1
+      if [ -z "$ANDROID_IGNORE_UNKNOWN_DEVICE" ]; then
+          echo "ERROR: unknown device $TARGET_DEVICE"
+          exit 1
+      fi
+      # If ANDROID_IGNORE_UNKNOWN_DEVICE is set, then ANDROID_TOOLCHAIN
+      # or ANDROID_ARCH should be set; Otherwise, ANDROID_ARCH
+      # defaults to 'arm' and the default ARM toolchain is used.
+      DEFINES="${DEFINES} skia_arch_type=${ANDROID_ARCH-arm}"
+      # If ANDROID_IGNORE_UNKNOWN_DEVICE is set, extra gyp defines can be
+      # added via ANDROID_GYP_DEFINES
+      DEFINES="${DEFINES} ${ANDROID_GYP_DEFINES}"
       ;;
   esac
 
   verbose "The build is targeting the device: $TARGET_DEVICE"
   exportVar DEVICE_ID $TARGET_DEVICE
 
   # setup the appropriate cross compiling toolchains
   source $SCRIPT_DIR/utils/setup_toolchain.sh
 
   DEFINES="${DEFINES} android_toolchain=${TOOLCHAIN_TYPE}"
@@ skipping 70 matching lines @@
       $ADB $DEVICE_SERIAL push $HOST_SRC $ANDROID_DST
     fi
   else
     echo -n "$ANDROID_DST "
     $ADB $DEVICE_SERIAL shell mkdir -p "$(dirname "$ANDROID_DST")"
     $ADB $DEVICE_SERIAL push $HOST_SRC $ANDROID_DST
   fi
 }
 
 setup_device "${DEVICE_ID}"