Fixes for re-enabling more MSVC level 4 warnings: media/ edition

Fixes for re-enabling more MSVC level 4 warnings: media/ edition

This contains fixes for the following sorts of issues:
* Signedness mismatch
* Assignment inside conditional
* Possibly-uninitialized local variable

This also contains a small number of other cleanups/simplifications to nearby
code.

BUG=81439
TEST=none

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=281888

[ddorwin, 2014-07-08 18:17:50]

https://codereview.chromium.org/377803004/diff/1/media/audio/audio_output_con...
File media/audio/audio_output_controller.cc (right):

https://codereview.chromium.org/377803004/diff/1/media/audio/audio_output_con...
media/audio/audio_output_controller.cc:226:
sync_reader_->UpdatePendingBytes(0xFFFFFFFF);
nit: kuint32max

https://codereview.chromium.org/377803004/diff/1/media/cast/rtcp/test_rtcp_pa...
File media/cast/rtcp/test_rtcp_packet_builder.cc (right):

https://codereview.chromium.org/377803004/diff/1/media/cast/rtcp/test_rtcp_pa...
media/cast/rtcp/test_rtcp_packet_builder.cc:68: const int padding = (6 -
(c_name.size() % 4)) % 4;
"case 2" was 4 and is now 0.

https://codereview.chromium.org/377803004/diff/1/media/video/capture/win/vide...
File media/video/capture/win/video_capture_device_factory_win.cc (right):

https://codereview.chromium.org/377803004/diff/1/media/video/capture/win/vide...
media/video/capture/win/video_capture_device_factory_win.cc:172: UINT32
name_size;
nit: initialize? ditto for id_size.

https://codereview.chromium.org/377803004/diff/1/media/video/capture/win/vide...
media/video/capture/win/video_capture_device_factory_win.cc:390:
DCHECK_EQ(VideoCaptureDevice::Name::DIRECT_SHOW,
nit: media/ code prefers "var, const" for code except googletest macros.

[Peter Kasting, 2014-07-08 18:39:15]

PTAL.

https://codereview.chromium.org/377803004/diff/1/media/audio/audio_output_con...
File media/audio/audio_output_controller.cc (right):

https://codereview.chromium.org/377803004/diff/1/media/audio/audio_output_con...
media/audio/audio_output_controller.cc:226:
sync_reader_->UpdatePendingBytes(0xFFFFFFFF);
On 2014/07/08 18:17:50, ddorwin wrote:
> nit: kuint32max

Done.

https://codereview.chromium.org/377803004/diff/1/media/cast/rtcp/test_rtcp_pa...
File media/cast/rtcp/test_rtcp_packet_builder.cc (right):

https://codereview.chromium.org/377803004/diff/1/media/cast/rtcp/test_rtcp_pa...
media/cast/rtcp/test_rtcp_packet_builder.cc:68: const int padding = (6 -
(c_name.size() % 4)) % 4;
On 2014/07/08 18:17:50, ddorwin wrote:
> "case 2" was 4 and is now 0.

Good catch.  Fixed.

Although I'm not sure it actually matters -- I assume this code is just here to
pad things out so the next item written will have 4-byte alignment, in which
case writing 4 bytes of padding is the same as writing no padding (except for
wasting some space?).  And the trybots seemed to pass, so it seems like
unittests don't rely on the distinction.

However, this patch isn't supposed to change behavior, so fixing it is the right
thing anyway.

https://codereview.chromium.org/377803004/diff/1/media/video/capture/win/vide...
File media/video/capture/win/video_capture_device_factory_win.cc (right):

https://codereview.chromium.org/377803004/diff/1/media/video/capture/win/vide...
media/video/capture/win/video_capture_device_factory_win.cc:172: UINT32
name_size;
On 2014/07/08 18:17:50, ddorwin wrote:
> nit: initialize? ditto for id_size.

I'm happy to do so if you like; there's no need to, since these are set
unconditionally in the function calls that immediately follow their declarations
(and the compiler is smart enough to figure that out).  Let me know and I'll
stick "= 0"s in.

https://codereview.chromium.org/377803004/diff/1/media/video/capture/win/vide...
media/video/capture/win/video_capture_device_factory_win.cc:390:
DCHECK_EQ(VideoCaptureDevice::Name::DIRECT_SHOW,
On 2014/07/08 18:17:50, ddorwin wrote:
> nit: media/ code prefers "var, const" for code except googletest macros.

Done.

[ddorwin, 2014-07-08 18:49:25]

lgtm

Thanks.

[Peter Kasting, 2014-07-08 18:49:58]

The CQ bit was checked by pkasting@chromium.org

[commit-bot: I haz the power, 2014-07-08 18:53:03]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/pkasting@chromium.org/377803004/20001

[commit-bot: I haz the power, 2014-07-08 23:47:15]

Change committed as 281888