Change Android toolchain to GCC 4.9.

build/android/adb_gdb

 #!/bin/bash
 #
 # 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.
 #
 
 # A generic script used to attach to a running Chromium process and
 # debug it. Most users should not use this directly, but one of the
 # wrapper scripts like adb_gdb_content_shell
@@ skipping 455 matching lines @@
 # $1: NDK install path
 # $2: NDK architecture name
 # $3: prebuilt sub-path to look for.
 # Out: file path, or empty if none is found.
 get_ndk_toolchain_prebuilt () {
   local NDK_DIR="${1%/}"
   local ARCH="$2"
   local SUBPATH="$3"
   local NAME="$(get_arch_toolchain_prefix $ARCH)"
   local FILE TARGET
-  FILE=$NDK_DIR/toolchains/$NAME-4.8/prebuilt/$SUBPATH
+  FILE=$NDK_DIR/toolchains/$NAME-4.9/prebuilt/$SUBPATH
   if [ ! -f "$FILE" ]; then
-    FILE=$NDK_DIR/toolchains/$NAME-4.9/prebuilt/$SUBPATH
+    FILE=$NDK_DIR/toolchains/$NAME-4.8/prebuilt/$SUBPATH
     if [ ! -f "$FILE" ]; then
-      FILE=$NDK_DIR/toolchains/$NAME-4.6/prebuilt/$SUBPATH
-      if [ ! -f "$FILE" ]; then
-        FILE=
-      fi
+      FILE=
     fi
   fi
   echo "$FILE"
 }
 
 # Find the path to an NDK's toolchain full prefix for a given architecture
 # $1: NDK install path
 # $2: NDK target architecture name
 # Out: install path + binary prefix (e.g.
 #      ".../path/to/bin/arm-linux-androideabi-")
@@ skipping 514 matching lines @@
 
 if [ "$VERBOSE" -gt 0 ]; then
   echo "### START $COMMANDS"
   cat $COMMANDS
   echo "### END $COMMANDS"
 fi
 
 log "Launching gdb client: $GDB $GDB_ARGS -x $COMMANDS"
 $GDB $GDB_ARGS -x $COMMANDS &&
 rm -f "$GDBSERVER_PIDFILE"