69 Commits

Author SHA1 Message Date
solenberg
88499ecaca Moving/renaming webrtc/common.h.
This file defines webrtc::Config which was mostly used by modules/audio_processing. The files webrtc/common.h, webrtc/common.cc and webrtc/test/common_unittests.cc are moved to modules/audio_processing and the few remaining uses of webrtc::Config are replaced with simpler code.

- For NetEq and pacing configuration, a VoEBase::ChannelConfig is passed to VoEBase::CreateChannel().
- Removes the need for VoiceEngine::Create(const Config& config). No need to store the webrtc::Config in VoE shared state.

BUG=webrtc:5879

Review-Url: https://codereview.webrtc.org/2307533004
Cr-Commit-Position: refs/heads/master@{#14109}
2016-09-07 14:34:45 +00:00
kjellander
a69d973267 Move webrtc/audio_*.h to webrtc/api/call
BUG=webrtc:5878
NOTRY=True

Review-Url: https://codereview.webrtc.org/2059703002
Cr-Commit-Position: refs/heads/master@{#13996}
2016-08-31 14:33:14 +00:00
peah
1bcfce5ff2 Deactivated the intelligibility enhancement functionality by default
NOTRY=true
BUG=

Review-Url: https://codereview.webrtc.org/2272423003
Cr-Commit-Position: refs/heads/master@{#13937}
2016-08-26 14:16:13 +00:00
peah
72a5645fdf Removed the deactivation of the level controller when there is a built-in AGC available
BUG=

Review-Url: https://codereview.webrtc.org/2240763002
Cr-Commit-Position: refs/heads/master@{#13853}
2016-08-22 19:09:02 +00:00
peah
4905f06878 Disable the software noise suppressor on iOS devices as that
functionality is always present in the hardware.

BUG=webrtc:6231

Review-Url: https://codereview.webrtc.org/2260173002
Cr-Commit-Position: refs/heads/master@{#13839}
2016-08-22 08:58:56 +00:00
ossu
d4e9f62ea7 Updated AudioDecoderFactory to list AudioCodecSpecs instead of SdpAudioFormats.
BUG=webrtc:5805

Review-Url: https://codereview.webrtc.org/2123923004
Cr-Commit-Position: refs/heads/master@{#13810}
2016-08-18 09:02:15 +00:00
ossu
c54071d8ab WebRtcVoiceEngine: Use AudioDecoderFactory to generate recv codecs.
Reland of https://codereview.webrtc.org/2072753002/ which broke
chromium due to how their build was setup. This issue should now be
resolved.

Changed WebRtcVoiceEngine to present receive codecs from the formats
provided by its decoder factory. Added supported formats to
BuiltinAudioDecoderFactory. Added helper functions for creating some
simple decoder factories for mocking.

Created a PayloadTypeMapper for assigning payload types to formats. I
think we'll eventually want to use this further up, or possibly in
both the audio and video sides. It would be best if the engines didn't
have to talk payload types at all, but it might be more difficult to
get around when payload types depend on each-other, like the RTX
codecs for video.

BUG=webrtc:5805
TBR=ivoc@webrtc.org

Review-Url: https://codereview.webrtc.org/2250683002
Cr-Commit-Position: refs/heads/master@{#13793}
2016-08-17 09:45:47 +00:00
maxmorin
1aee0b5bd9 Remove old methods in AudioTransport, make it pass a gn build
when building with default warnings.

This is in preparation for making a gn target for audio_device_tests.

BUG=webrtc:6170, webrtc:163
NOTRY=True

Review-Url: https://codereview.webrtc.org/2219653004
Cr-Commit-Position: refs/heads/master@{#13759}
2016-08-15 18:46:28 +00:00
aleloi
84ef615a5d Removed calls to VoE::SetPlayout() from WebRTCVoiceEngine.
This is part of rewriting the ConferenceMixer and OutputMixer.

Calls are instead routed through AudioReceiveStream::Start/Stop.

NOTRY=True

Review-Url: https://codereview.webrtc.org/2206223002
Cr-Commit-Position: refs/heads/master@{#13636}
2016-08-04 12:28:28 +00:00
mflodman
86cc6ffc7c Variable audio bitrate.
This is a first CL wiring up AudioSendStream to BitrateAllocator. This
is still experimental and there is a test added for the audio only case,
combined audio video variable bitrate test cases will be added as a
follow up.

BUG=5079

Review-Url: https://codereview.webrtc.org/2165743003
Cr-Commit-Position: refs/heads/master@{#13527}
2016-07-26 11:44:12 +00:00
ossu
f93be584f7 Revert of WebRtcVoiceEngine: Use AudioDecoderFactory to generate recv codecs. (patchset #10 id:200001 of https://codereview.webrtc.org/2072753002/ )
Reason for revert:
For some reason, payload_type_mapper.cc is not being picked up in Chrome builds, leading to undefined references. Reverting while investigating.

Original issue's description:
> WebRtcVoiceEngine: Use AudioDecoderFactory to generate recv codecs.
>
> Changed WebRtcVoiceEngine to present receive codecs from the formats
> provided by its decoder factory. Added supported formats to
> BuiltinAudioDecoderFactory. Added helper functions for creating some
> simple decoder factories for mocking.
>
> Created a PayloadTypeMapper for assigning payload types to formats. I
> think we'll eventually want to use this further up, or possibly in
> both the audio and video sides. It would be best if the engines didn't
> have to talk payload types at all, but it might be more difficult to
> get around when payload types depend on each-other, like the RTX
> codecs for video.
>
> This CL also includes some changes to rtc::Optional. I've put them in
> a separate CL that should (or should not) land first, making these
> changes void.
> See: https://codereview.webrtc.org/2072713002/
>
> BUG=webrtc:5805
>
> Committed: https://crrev.com/95eb1ba0db79d8fd134ae61b0a24648598684e8a
> Cr-Commit-Position: refs/heads/master@{#13459}

TBR=ivoc@webrtc.org,tina.legrand@webrtc.org,tommi@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:5805

Review-Url: https://codereview.webrtc.org/2151453002
Cr-Commit-Position: refs/heads/master@{#13460}
2016-07-13 13:31:37 +00:00
ossu
95eb1ba0db WebRtcVoiceEngine: Use AudioDecoderFactory to generate recv codecs.
Changed WebRtcVoiceEngine to present receive codecs from the formats
provided by its decoder factory. Added supported formats to
BuiltinAudioDecoderFactory. Added helper functions for creating some
simple decoder factories for mocking.

Created a PayloadTypeMapper for assigning payload types to formats. I
think we'll eventually want to use this further up, or possibly in
both the audio and video sides. It would be best if the engines didn't
have to talk payload types at all, but it might be more difficult to
get around when payload types depend on each-other, like the RTX
codecs for video.

This CL also includes some changes to rtc::Optional. I've put them in
a separate CL that should (or should not) land first, making these
changes void.
See: https://codereview.webrtc.org/2072713002/

BUG=webrtc:5805

Review-Url: https://codereview.webrtc.org/2072753002
Cr-Commit-Position: refs/heads/master@{#13459}
2016-07-13 13:05:32 +00:00
ivoc
14d5dbe5b3 Reland of "Move RtcEventLog object from inside VoiceEngine to Call.", "Fix to make the start/stop functions for the Rtc Eventlog non-virtual." and "Fix for RtcEventLog ObjC interface"
The breaking tests in Chromium have been temporarily disabled, they will be fixed and reenabled soon.

Original CLs: https://codereview.webrtc.org/1748403002/, https://codereview.webrtc.org/2107253002/ and https://codereview.webrtc.org/2106103003/.

TBR=solenberg@webrtc.org,tommi@webrtc.org,stefan@webrtc.org,terelius@webrtc.org,tkchin@webrtc.org
BUG=webrtc:4741, webrtc:5603, chromium:609749

Review-Url: https://codereview.webrtc.org/2110113003
Cr-Commit-Position: refs/heads/master@{#13379}
2016-07-04 14:07:03 +00:00
ivoc
9e03c3b372 Revert of Move RtcEventLog object from inside VoiceEngine to Call. (patchset #16 id:420001 of https://codereview.webrtc.org/1748403002/ )
Reason for revert:
Reverting all CLs related to moving the eventlog, as they break Chromium tests.

Original issue's description:
> Move RtcEventLog object from inside VoiceEngine to Call.
>
> In addition to moving the logging object itself, this also moves the interface from PeerConnectionFactory to PeerConnection, which makes more sense for this functionality. An API parameter to set an upper limit to the size of the logfile is introduced.
> The old interface on PeerConnectionFactory is not removed in this CL, because it is called from Chrome, it will be removed after Chrome is updated to use the PeerConnection interface.
>
> BUG=webrtc:4741,webrtc:5603,chromium:609749
> R=solenberg@webrtc.org, stefan@webrtc.org, terelius@webrtc.org, tommi@webrtc.org
>
> Committed: https://crrev.com/1895526c6130e3d0e9b154f95079b8eda7567016
> Cr-Commit-Position: refs/heads/master@{#13321}

TBR=solenberg@webrtc.org,tommi@webrtc.org,stefan@webrtc.org,terelius@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:4741,webrtc:5603,chromium:609749

Review-Url: https://codereview.webrtc.org/2111813002
Cr-Commit-Position: refs/heads/master@{#13340}
2016-06-30 07:59:49 +00:00
peah
a3333bfafb This CL adds activation logic of the new APM level control
functionality and exposes the functionality using the
MediaConstraints.

The exposing of the feature through the  MediaConstraints
was done similarly to what was done for the intelligibility
enhancer in the CL
https://codereview.webrtc.org/1952123003

This CL is dependent on the CL https://codereview.webrtc.org/2090583002/ which contains
the level control functionality.

NOTRY=true
BUG=webrtc:5920

Review-Url: https://codereview.webrtc.org/2095563002
Cr-Commit-Position: refs/heads/master@{#13336}
2016-06-30 07:02:41 +00:00
Ivo Creusen
1895526c61 Move RtcEventLog object from inside VoiceEngine to Call.
In addition to moving the logging object itself, this also moves the interface from PeerConnectionFactory to PeerConnection, which makes more sense for this functionality. An API parameter to set an upper limit to the size of the logfile is introduced.
The old interface on PeerConnectionFactory is not removed in this CL, because it is called from Chrome, it will be removed after Chrome is updated to use the PeerConnection interface.

BUG=webrtc:4741,webrtc:5603,chromium:609749
R=solenberg@webrtc.org, stefan@webrtc.org, terelius@webrtc.org, tommi@webrtc.org

Review URL: https://codereview.webrtc.org/1748403002 .

Cr-Commit-Position: refs/heads/master@{#13321}
2016-06-29 11:57:01 +00:00
solenberg
217fb66e16 Add AudioReceiveStream::SetGain() method and use that in WVoMC::SetOutputVolume().
Removes the need to use VoEVolume::SetChannelOutputVolumeScaling().

BUG=webrtc:4690

Review-Url: https://codereview.webrtc.org/2062193002
Cr-Commit-Position: refs/heads/master@{#13194}
2016-06-17 15:30:58 +00:00
solenberg
4a0f7b508d - Remove use of VoERTP_RTCP::SetLocalSSRC() for receive streams; recreate them instead.
- Remove VoERTP_RTCP from VoEWrapper and FakeWebRtcVoiceEngine.

BUG=webrtc:4690

Review-Url: https://codereview.webrtc.org/2072783002
Cr-Commit-Position: refs/heads/master@{#13174}
2016-06-16 20:07:39 +00:00
solenberg
9421853e17 Add AudioSendStream::SetMuted() method and use it in WVoMC::MuteStream().
Removes the need to use VoEVolume::SetInputMute()/GetInputMute().

BUG=webrtc:4690
NOTRY=true

Review-Url: https://codereview.webrtc.org/2066973002
Cr-Commit-Position: refs/heads/master@{#13172}
2016-06-16 17:53:28 +00:00
kwiberg
edaa849013 WebRtcVoiceCodecs: Eliminate some useless copying
Review-Url: https://codereview.webrtc.org/2067453002
Cr-Commit-Position: refs/heads/master@{#13151}
2016-06-15 11:34:53 +00:00
solenberg
8189b02fea Configure VoE NACK through AudioReceiveStream::Config, for receive streams. Also minor refactoring of WVoE unit test.
BUG=webrtc:4690

Review-Url: https://codereview.webrtc.org/2060813002
Cr-Commit-Position: refs/heads/master@{#13140}
2016-06-14 19:13:07 +00:00
solenberg
971cab0d93 Configure VoE NACK through AudioSendStream::Config, for send streams.
BUG=webrtc:4690

Review-Url: https://codereview.webrtc.org/1955363003
Cr-Commit-Position: refs/heads/master@{#13136}
2016-06-14 17:02:46 +00:00
solenberg
05b9803c8e Removed unused GetOutputVolume() and SetOutputVolume() from MediaEngineInterface.
BUG=webrtc:4690

Review-Url: https://codereview.webrtc.org/2059403002
Cr-Commit-Position: refs/heads/master@{#13135}
2016-06-14 15:59:54 +00:00
kwiberg
6806136aec Remove RED support from WebRtcVoiceEngine/MediaChannel
This CL was originally written by solenberg@webrtc.org:
https://codereview.webrtc.org/1928233003/

BUG=webrtc:4690, webrtc:5922

Review-Url: https://codereview.webrtc.org/2051073002
Cr-Commit-Position: refs/heads/master@{#13133}
2016-06-14 15:04:53 +00:00
ossu
dedfd28a52 Support for two audio codec lists down into WebRtcVoiceEngine.
Added the plumbing necessary to get two different lists of codecs from
WebRtcVoiceEngine up to MediaSessionDescriptionFactory.

This should be the last step in this set of CLs. Once
https://codereview.webrtc.org/1991233004/ has landed, it's possible to
implement the ReceiveCodecs getter with the info from the
AudioDecoderFactory. The factory needs to be updated to actually
produce the correct list, as well.

BUG=webrtc:5805

Review-Url: https://codereview.webrtc.org/2013053002
Cr-Commit-Position: refs/heads/master@{#13131}
2016-06-14 14:12:46 +00:00
ossu
29b1a8d7ec Moved creation of AudioDecoderFactory to inside PeerConnectionFactory.
CreatePeerConnectionFactory does not yet expose the ability to set the
factory from the outside.

Added notry due to android_dbg being broken.

NOTRY=True
BUG=webrtc:5805

Review-Url: https://codereview.webrtc.org/1991233004
Cr-Commit-Position: refs/heads/master@{#13112}
2016-06-13 14:35:01 +00:00
isheriff
6f8d686d35 Remove use of RtpHeaderExtension and clean up
Currently there are two structs that are identical and track extension details:
webrtc::RtpExtension
cricket::RtpHeaderExtension

The use of the structs is mixed in the code to track the extensions being
supported. This results in duplicate definition of
the URI constants and there is code to convert between the two structs.

Clean up to use a single RtpHeader throughout the codebase. The actual location
of RtpHeader may change in future (perhaps to be located in api/). Additionally,
this CL renames some of the constants to clarify Uri and Id use.

BUG= webrtc:5895

Review-Url: https://codereview.webrtc.org/1984983002
Cr-Commit-Position: refs/heads/master@{#12924}
2016-05-26 18:25:04 +00:00
Alejandro Luebs
c9b0c26e0c Surface the IntelligibilityEnhancer on MediaConstraints
R=henrika@webrtc.org, peah@webrtc.org, tommi@webrtc.org

Review URL: https://codereview.webrtc.org/1952123003 .

Cr-Commit-Position: refs/heads/master@{#12763}
2016-05-16 22:32:45 +00:00
Taylor Brandstetter
db0cd9e774 Adding getParameters/setParameters APIs to RtpReceiver.
This is similar to how a "receive" method is used to apply
RtpParameters to an RtpReceiver in ORTC. Currently, SetParameters
doesn't allow changing the parameters, so the main use of the API is
to retrieve the set of configured codecs. But other uses will likely
be made possible in the future.

R=glaznev@webrtc.org, pthatcher@webrtc.org, tkchin@webrtc.org

Review URL: https://codereview.webrtc.org/1917193008 .

Cr-Commit-Position: refs/heads/master@{#12761}
2016-05-16 18:40:38 +00:00
ivoc
c1513ee1a3 Add a parameter to set a maximum file size when starting an RTC event log on the PeerConnectionFactory API.
The caller can set a negative or zero file size to avoid using a limit.
BUG=

Review-Url: https://codereview.webrtc.org/1974453002
Cr-Commit-Position: refs/heads/master@{#12730}
2016-05-13 15:30:44 +00:00
deadbeef
b56069e650 Enable NACK for audio even if there are no send streams.
BUG=webrtc:5762

Review-Url: https://codereview.webrtc.org/1950963003
Cr-Commit-Position: refs/heads/master@{#12641}
2016-05-06 11:57:11 +00:00
solenberg
31fec40482 Set rtcp_send_transport for AudioReceiveStreams. This was forgotten in https://codereview.webrtc.org/1909333002/.
BUG=webrtc:4690, webrtc:5079, webrtc:5762

Review-Url: https://codereview.webrtc.org/1951833002
Cr-Commit-Position: refs/heads/master@{#12640}
2016-05-06 09:13:22 +00:00
Taylor Brandstetter
55dd70842c Support RtpEncodingParameters::active in voice engine.
R=solenberg@webrtc.org

Review URL: https://codereview.webrtc.org/1943073003 .

Cr-Commit-Position: refs/heads/master@{#12615}
2016-05-03 20:50:24 +00:00
solenberg
05e61edd8f Remove usage of VoENetwork from VoEWrapper and FakeWebRtcVoiceEngine.
BUG=webrtc:4690

Review-Url: https://codereview.webrtc.org/1934513002
Cr-Commit-Position: refs/heads/master@{#12566}
2016-04-29 16:05:35 +00:00
mflodman
3d7db263b9 Switch voice transport to use Call and Stream instead of VoENetwork.
VoENetwork is kept for now, but is not really used anylonger.

webrtcvoiceengine is changed to have the same behavior for unsignaled
ssrc as video has, which is reflected by disabling one test case and
this will be discussed and followed up.

BUG=webrtc:5079

TBR=tommi

Review-Url: https://codereview.webrtc.org/1909333002
Cr-Commit-Position: refs/heads/master@{#12555}
2016-04-29 07:57:21 +00:00
deadbeef
8034614b81 Cap the send bitrate for opus and iSAC before passing down to VoE.
The voice engine expects send bitrates no more than the maximum for the
codec. For example, 510kbps for opus. So if "b=AS" sets a maximum above
the codec maximum, WebRtcVoiceEngine needs to cap it.

BUG=603690

Review-Url: https://codereview.webrtc.org/1920123002
Cr-Commit-Position: refs/heads/master@{#12537}
2016-04-27 21:17:15 +00:00
kwiberg
4485ffb58d #include "webrtc/base/constructormagic.h" where appropriate
Any file that uses the RTC_DISALLOW_* macros should #include
"webrtc/base/constructormagic.h", but a shocking number of them don't.
This causes trouble when we try to wean files off of #including
scoped_ptr.h, since a bunch of files get their constructormagic macros
only from there.

Rather than fixing these errors one by one as they turn up, this CL
simply ensures that every file in the WebRTC tree that uses the
RTC_DISALLOW_* macros #includes "webrtc/base/constructormagic.h".

BUG=webrtc:5520

Review URL: https://codereview.webrtc.org/1917043005

Cr-Commit-Position: refs/heads/master@{#12509}
2016-04-26 15:14:48 +00:00
Taylor Brandstetter
0cd086b70e Adding codecs to the RtpParameters returned by an RtpSender.
Contains every field except for sdpFmtpLine.
Setting a reordered list of codecs is not yet supported.

R=glaznev@webrtc.org, pthatcher@webrtc.org, skvlad@webrtc.org, tkchin@webrtc.org

Review URL: https://codereview.webrtc.org/1885473004 .

Cr-Commit-Position: refs/heads/master@{#12453}
2016-04-20 23:23:22 +00:00
Honghai Zhang
0e533ef487 Update the call when the network route changes
so that BWE can be updated promptly.

BUG=webrtc:5726
R=mflodman@webrtc.org, pbos@webrtc.org, pthatcher@google.com, pthatcher@webrtc.org, stefan@webrtc.org

Review URL: https://codereview.webrtc.org/1844773002 .

Cr-Commit-Position: refs/heads/master@{#12432}
2016-04-19 22:41:53 +00:00
solenberg
cc74dbac4f Remove unused cricket::AudioFrame class.
BUG=

Review URL: https://codereview.webrtc.org/1891933002

Cr-Commit-Position: refs/heads/master@{#12379}
2016-04-15 13:41:17 +00:00
solenberg
d53a3f9758 Early initialize recording on the ADM from WebRtcVoiceMediaChannel.
BUG=webrtc:4690

Review URL: https://codereview.webrtc.org/1827263002

Cr-Commit-Position: refs/heads/master@{#12369}
2016-04-14 20:56:45 +00:00
deadbeef
67cf2c1294 Removing preference field from cricket::Codec.
This field only existed as an implementation detail for getting the
codecs sorted, so it doesn't need to be in the public interface.
It cluttered the code and undesirably affected codec comparisons,
causing the video encoder to be reconfigured if a codec's preference
changed but nothing else did.

BUG=webrtc:5690

Review URL: https://codereview.webrtc.org/1845673002

Cr-Commit-Position: refs/heads/master@{#12349}
2016-04-13 17:07:24 +00:00
solenberg
6d6e7c5e1a Fix bug causing audio to stop being sent when AudioSendStreams are recreated.
BUG=webrtc:5772

Review URL: https://codereview.webrtc.org/1881793006

Cr-Commit-Position: refs/heads/master@{#12347}
2016-04-13 16:07:38 +00:00
solenberg
5b5129a2ad Replace a few calls to VoEHardware with direct calls on the ADM, in WVoMC.
BUG=webrtc:4690

Review URL: https://codereview.webrtc.org/1875483002

Cr-Commit-Position: refs/heads/master@{#12293}
2016-04-08 12:35:55 +00:00
skvlad
e0d4637bea Allow applications to control audio send bitrate through RtpParameters.
This change builds on top of the refactoring in https://codereview.webrtc.org/1841083008/, and enables WebRTC client applications to control the max send bitrate for every audio stream through RtpParameters.

The AudioSendStream now stores the last codec spec, and whenever a global or per-stream bitrate limit changes, the effective limit (smaller of the two) is recomputed and the codec is reconfigured with that bitrate.

TBR=pthatcher
BUG=

Review URL: https://codereview.webrtc.org/1847353004

Cr-Commit-Position: refs/heads/master@{#12290}
2016-04-08 05:59:32 +00:00
solenberg
ff97631e3c - Add temporary VoEBase::audio_device_module() method.
- Remove WVoE::SetAudioDeviceModule() - the ADM is now supplied in ctor.
- Remove WVoE::Init() and WVoE::Terminate().
- Remove MediaEngineInterface::Terminate().

BUG=webrtc:4690

Review URL: https://codereview.webrtc.org/1830213002

Cr-Commit-Position: refs/heads/master@{#12173}
2016-03-31 06:28:56 +00:00
Honghai Zhang
cc411c0599 Reset the BWE when the network changes.
Currently "Resetting the BWE" does nothing yet. This CL passes the correct signaling to the bandwidth estimator.

BUG=
R=pthatcher@webrtc.org

Review URL: https://codereview.webrtc.org/1803063004 .

Cr-Commit-Position: refs/heads/master@{#12154}
2016-03-30 00:27:36 +00:00
Henrik Kjellander
b252856d10 Remove all uses of the HAVE_CONFIG_H define.
BUG=
R=henrik.lundin@webrtc.org, pthatcher@google.com, stefan@webrtc.org, tommi@webrtc.org

Review URL: https://codereview.webrtc.org/1820023004 .

Cr-Commit-Position: refs/heads/master@{#12141}
2016-03-29 15:47:28 +00:00
skvlad
7a43d253f9 Make the audio channel communicate network state changes to the call.
This change enables voice-only calls to keep track of the network state.
This is only a partial fix - the last modality to change state controls
the state for the entire call, so a call with a failed video transport
will also stop sending audio packets. Handling this condition correctly
would require the call to keep track of network state for each media
type separately, and take care of conditions such as a failed video
channel getting removed, while a functioning audio channel remains.

BUG=webrtc:5307

Review URL: https://codereview.webrtc.org/1757683002

Cr-Commit-Position: refs/heads/master@{#12093}
2016-03-22 22:32:31 +00:00
jbauch
eec21bdae3 Reland Use CopyOnWriteBuffer instead of Buffer to avoid unnecessary copies.
This CL removes copy and assign support from Buffer and changes various
parameters from Buffer to CopyOnWriteBuffer so they can be passed along
and copied without actually copying the underlying data.

With this changed some parameters to be "const" and fixed an issue when
creating a CopyOnWriteBuffer with empty data.

BUG=webrtc:5155

Review URL: https://codereview.webrtc.org/1823503002

Cr-Commit-Position: refs/heads/master@{#12062}
2016-03-20 13:15:48 +00:00