Reland 967793002 Linux Video Capture: Add V4L2VideoCaptureDelegate{Single,Multi}Plane

Reland 967793002 Linux Video Capture: Add V4L2VideoCaptureDelegate{Single,Multi}Plane

FileVCD did not specify a Capture Api Type in Linux
platforms, hence the check failed down the road.

Original description: -----------------------------------------

This CL adds support for V4L2 MPLANE Capture Api.
Only supported format is YUV420M triplanar.

A new method is added to VideoCaptureDeviceClient,
namely OnIncomingCapturedYuvData(...), which forces
adding MOCKing here and there, and its own
implementation.

V4L2 MMAP API works via user mmap()ing a number of
buffer allocated by V4L2 capture device. If those
buffers are not correctly munmap()ed, bad things (c)
happen. In light of this, the manual buffer lifetime
management is changed to automatic one. Construction
(mmap()ing) of those called BufferTracker is
planarity specific (i.e. there's one such ctor in
each of BufferTracker{S,M}Plane), while the dtor
is generic and the same.

ToT class diagram:
     +------------------------------------+
     | VideoCaptureDeviceLinux            |
     |            +----------------------+|
     | <<ref>> -->| V4L2CaptureDelegate  ||
     |   cnt      |  (struct Buffer)     ||
     |            +----------------------+|
     +------------------------------------+

This CL class scheme:

 +--------------------------+
 | VideoCaptureDeviceLinux  |
 |                          |
 | <<ref_cnt>> ---+         |
 +----------------|---------+
 +----------------v-----------+ v4l2_capture_delegate.{cc,h}
 | +-----------------------+  |
 | |V4L2CaptureDelegate    |  |
 | |  (class BufferTracker)|  |
 | +-----------------------+  |
 +-------^------------------^-+
         |                  |
    +----|-------+ +--------|--+ v4l2_capture_delegate_multi_plane.{cc,h}
    | SPlane     | | MPlane    |
    | (BTSplane) | | (BTMPlane)|
    |            | +-----------+
    +------------+ v4l2_capture_delegate_single_plane.{cc,h}

- VCDevice works on the premise that its calls into
 VCDevice::Client::OnIncomingWhatever() are synchronous.
 That assumption is respected here.

- A bit of cleanup is done in OnIncomingCaptureData(),
 in what regards rotation/crop/odd sizes. A unit test
 is subsequently added.

- VideoCaptureDeviceFactory labels the devices as
 Single or Multi Planar. That labeling capture_api_type()
 needs to ripple through a bunch of files, causing some
 otherwise uninteresting changes in the patchsets.

BUG=441836
TEST= Compile and insmod vivid.ko into a kernel,
with options for supporting MPLANE api (multiplanar=2)
then capture using patched Chromium. Current vivid
does _not_ support any common Mplane format, needs
a patch:

https://github.com/miguelao/linux/tree/adding_yu12_yv12_nv12_nv21___mplane_formats___with_mods_for_kernel_3_13

that needs to be compiled against ubuntu sources 3.13 etc.

For even better coverage, use a normal WebCam and
navigate to http://goo.gl/fUcIiP, then open both
the MPlane camera mentioned in the previous paragraph
and the "normal" webcam (this is,partially, how I
try it).

TBR= posciak@chromium.org, perkj@chromium.org, magjed@chromium.org, dalecurtis@chromium.org

Committed: https://crrev.com/03b770885dbf8d873c38f72b98fd4faddf80633e
Cr-Commit-Position: refs/heads/master@{#321856}

[mcasas, 2015-03-23 18:08:40]

The CQ bit was checked by mcasas@chromium.org

[commit-bot: I haz the power, 2015-03-23 18:09:12]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1026073002/20001

[commit-bot: I haz the power, 2015-03-23 21:28:52]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-03-23 21:29:22]

Patchset 2 (id:??) landed as
https://crrev.com/03b770885dbf8d873c38f72b98fd4faddf80633e
Cr-Commit-Position: refs/heads/master@{#321856}