resolved conflicts for merge of 70ab38a5 to master

bootanimation ends at: 33790 31230 (-2560)

Systrace

--------

Systrace [1] can be used for obtaining performance analysis reports during boot

time on userdebug or eng builds.

Here is an example of trace events of "wm" and "am" categories:

  $ANDROID_BUILD_TOP/external/chromium-trace/systrace.py wm am --boot

This command will cause the device to reboot. After the device is rebooted and

the boot sequence has finished, the trace report is obtained from the device

and written as trace.html on the host by hitting Ctrl+C.

LIMITATION

Recording trace events is started after persistent properties are loaded, so

the trace events that are emitted before that are not recorded. Several

services such as vold, surfaceflinger, and servicemanager are affected by this

limitation since they are started before persistent properties are loaded.

Zygote initialization and the processes that are forked from the zygote are not

affected.

[1] http://developer.android.com/tools/help/systrace.html

Debugging init

--------------

By default, programs executed by init will drop stdout and stderr into

    mkdir /data/local 0751 root root

    mkdir /data/misc/media 0700 media media

    mkdir /data/misc/vold 0700 root root

    mkdir /data/misc/boottrace 0771 system shell

    # For security reasons, /data/local/tmp should always be empty.

    # Do not place files or directories in /data/local/tmp

# Allow only the shell group to read and truncate the kernel trace.

    chown root shell /sys/kernel/debug/tracing/trace

    chmod 0660 /sys/kernel/debug/tracing/trace

on property:persist.debug.atrace.boottrace=1

    start boottrace

# Run atrace with the categories written in a file

service boottrace /system/bin/atrace --async_start -f /data/misc/boottrace/categories

    disabled

    oneshot