Revert of Mac Video Capture Device: split VCD into VCD and Factory.

Revert of Mac Video Capture Device: split VCD into VCD and Factory. (https://codereview.chromium.org/265263004/)

Reason for revert:
Some backoffice bots broke due to |kUseFakeDeviceForMediaStream| not being correctly defined - reverting until M36 storm passes and then I'll figure those out.

Original issue's description:
> Mac Video Capture Device: split VCD into VCD and Factory.
> 
> VideoCaptureDeviceMac includes factory and non-factory parts.
> This CL splits them into VideoCaptureDeviceMac and 
> VideoCaptureDeviceFactoryMac. The latter inherits the previous
> class' static methods: Create(), GetDeviceNames() and 
> GetDeviceSupportedFormats().
> 
> All video factory code previously in MediaStreamManager is
> moved into VideoCaptureFactory. This includes the use
> of the flag |kUseFakeDeviceForMediaStream|.
> This flag is moved correspondingly into media_switches.cc --
> (but note that this flag is still used in MediaStreamManager for 
> the Fake Audio parts). File media_switches.cc is
> included in several test files where the flag is used.
> 
> 
> VideoCaptureDeviceTest is splitted as well into:
> a) Tests that were exercising only the FakeVCD 
> (FakeVideoCaptureDeviceTest).
> b) All other tests, that use the underlying OS webcam.
> This VideoCaptureDeviceTest gets a Factory and uses it
> instead of static methods.
> 
> A unit test is added to VCDFMac, doing little for the moment
> but I'm planning to add support for testing at least the
> blacklisting -- req from rsesek@ in another CL.
> 
> BUG=288562, 323913, 255552
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=269271

TBR=perkj@chromium.org,jochen@chromium.org,dalecurtis@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=288562, 323913, 255552
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=269312

[mcasas, 2014-05-09 14:28:15]

Created Revert of Mac Video Capture Device: split VCD into VCD and Factory.

[commit-bot: I haz the power, 2014-05-09 14:34:11]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/mcasas@chromium.org/273063002/1

[commit-bot: I haz the power, 2014-05-09 15:27:43]

Change committed as 269312