[Platform] Enable to get a partial data of SharedBuffer

This CL creates a method to get a partial data of SharedBuffer.

This new method allows us to read a part of a buffer
with specifying starting position and length as a copy.

BUG=634935
Committed: https://crrev.com/4b42aa218b8ebeef9ef8eef3109df7d89214d38d
Cr-Commit-Position: refs/heads/master@{#411951}

[peria, 2016-08-15 07:22:39]

Description was changed from

==========
Add a new method in SharedBuffer to get a part of it


BUG=634935
==========

to

==========
This CL creates a method to get a partial data of SharedBuffer.

This new method allows us to read a part of a buffer
with specifying starting position and length as a copy.


BUG=634935
==========

[peria, 2016-08-15 07:25:07]

peria@chromium.org changed reviewers:
+ haraken@chromium.org

[peria, 2016-08-15 07:25:08]

PTL.

[haraken, 2016-08-15 07:39:12]

LGTM

[peria, 2016-08-15 08:05:56]

The CQ bit was checked by peria@chromium.org

[commit-bot: I haz the power, 2016-08-15 08:06:01]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-08-15 09:25:30]

Description was changed from

==========
This CL creates a method to get a partial data of SharedBuffer.

This new method allows us to read a part of a buffer
with specifying starting position and length as a copy.


BUG=634935
==========

to

==========
This CL creates a method to get a partial data of SharedBuffer.

This new method allows us to read a part of a buffer
with specifying starting position and length as a copy.


BUG=634935
==========

[commit-bot: I haz the power, 2016-08-15 09:25:31]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-08-15 09:27:40]

Description was changed from

==========
This CL creates a method to get a partial data of SharedBuffer.

This new method allows us to read a part of a buffer
with specifying starting position and length as a copy.


BUG=634935
==========

to

==========
This CL creates a method to get a partial data of SharedBuffer.

This new method allows us to read a part of a buffer
with specifying starting position and length as a copy.

BUG=634935

Committed: https://crrev.com/4b42aa218b8ebeef9ef8eef3109df7d89214d38d
Cr-Commit-Position: refs/heads/master@{#411951}
==========

[commit-bot: I haz the power, 2016-08-15 09:27:41]

Patchset 1 (id:??) landed as
https://crrev.com/4b42aa218b8ebeef9ef8eef3109df7d89214d38d
Cr-Commit-Position: refs/heads/master@{#411951}