Connect to signals for various states inside of webrtcbin

Internal callbacks for state types below are added.
 - peer connection state
 - signaling state
 - ICE gathering state
 - ICE connection state

These are implementation in webrtcbin based on
 - https://w3c.github.io/webrtc-pc/#state-definitions

These will be utilized for dividing current states of this API set
into more steps with further patches.

[Version] 0.1.20
[Issue Type] Improvement

Change-Id: I28c540bf69952070485d09d9e06a6b9635caf93a
Signed-off-by: Sangchul Lee <sc11.lee@samsung.com>

Add API set for ICE candidate

These correspond to the 'onicecandidate' property
and 'addIceCandidate' method of the RTCPeerConnection
respectively.

Functions are added as below.
 - webrtc_set_ice_candidate_cb()
 - webrtc_unset_ice_candidate_cb()
 - webrtc_add_ice_candidate()

Test cases for these functions are added to webrtc_test.
Some release handle information are added to @remarks.

[Version] 0.1.19
[Issue Type] API

Change-Id: Ib6675943d3aa2917360b8de82a4e76700089c961
Signed-off-by: Sangchul Lee <sc11.lee@samsung.com>

webrtc_test: Revise setting remote description

It should be set after receiving it from server.

[Version] 0.1.18
[Issue Type] Test application

Change-Id: I50f1ef6beefd24238fa2e9df1e6a890887262d43
Signed-off-by: Sangchul Lee <sc11.lee@samsung.com>

webrtc_test: Add code to show setting and server status

[Version] 0.1.17
[Issue Type] Test application

Change-Id: I2a5194af68f695909b874f64f43bf539746d8a2f
Signed-off-by: Sangchul Lee <sc11.lee@samsung.com>

webrtc_test: Add more menu regarding signaling server

Menu for request session of remote peer id and
sending local description to server are added.

[Version] 0.1.16
[Issue Type] Test application

Change-Id: I97fd587d656e237fa82468a1c36f18c7dfb3000a
Signed-off-by: Sangchul Lee <sc11.lee@samsung.com>

webrtc_test: Add support for connecting to a signaling server

A menu for this is added to the test application.
 : cs. Connect to the signaling server

We assume that the signaling server provides websocket interface.
The logics for handshaking from a peer to the server can be
different in each server. The upcoming patch will address this
handshaking protocol for demo server.

[Version] 0.1.15
[Issue Type] Test application

Change-Id: I95ed1ab2d0b6cf44d5d24cd39b8559d6be0024c4
Signed-off-by: Sangchul Lee <sc11.lee@samsung.com>

webrtc_test: Check URL length before setting it

Two similar functions are merged into one.

[Version] 0.1.14
[Issue Type] Test application

Change-Id: I6e0760278b177eef6a3d835fe2d59910ca91a6b2
Signed-off-by: Sangchul Lee <sc11.lee@samsung.com>

webrtc_test: Fix typo - signalling to signaling

[Version] 0.1.13
[Issue Type] Typo fix

Change-Id: I4edaf287387842f2c04df52c544b546f3ff80bda
Signed-off-by: Sangchul Lee <sc11.lee@samsung.com>

Add API set for error callback

Functions are added as below.
 - webrtc_set_error_cb()
 - webrtc_unset_error_cb()

Test cases for these functions are added to webrtc_test.

[Version] 0.1.12
[Issue Type] API

Change-Id: Ib4393388e3e440d88fd5f1aa013bb3d62c7b92c2
Signed-off-by: Sangchul Lee <sc11.lee@samsung.com>

Add API set for state changed callback

Functions are added as below.
 - webrtc_set_state_changed_cb()
 - webrtc_unset_state_changed_cb()

Test cases for these functions are added to webrtc_test.

[Version] 0.1.11
[Issue Type] API

Change-Id: I384ce3da148cd6181795a998abb33b98855543c2
Signed-off-by: Sangchul Lee <sc11.lee@samsung.com>

Add webrtc_set_local[remote]_description() API

It corresponds to the setLocal[Remote]Description() method
of the RTCPeerConnection respectively.

[Version] 0.1.10
[Issue Type] API

Change-Id: Ie1e2ddad5d6b3cd5741b034d14d07f13625d492c
Signed-off-by: Sangchul Lee <sc11.lee@samsung.com>

Add webrtc_create_offer() and webrtc_create_answer() API

It corresponds to the createOffer() and createAnswer() method
of the RTCPeerConnection respectively.

[Version] 0.1.9
[Issue Type] API

Change-Id: Ib2c3fc35a5b9adc7a2d35ad92f7001869a7d9dc4
Signed-off-by: Sangchul Lee <sc11.lee@samsung.com>

Add webrtc_set[unset]_negotiation_needed_cb() API

It corresponds to the negotiationneeded event of RTCPeerConnection.
Internal functions regarding signal connection are added.

[Version] 0.1.8
[Issue Type] API

Change-Id: I14587a3073315d8b2cece0b415d04799747d2ed0
Signed-off-by: Sangchul Lee <sc11.lee@samsung.com>

Add codes to set STUN server URL

Implementation of webrtc_set_stun_server().

[Version] 0.1.7
[Issue Type] Implementation

Change-Id: Iba22cda51ff9c0bde7fed270dc6878377b1510d0
Signed-off-by: Sangchul Lee <sc11.lee@samsung.com>

Add macro for log - LOG_ERROR_IF_REACHED()

[Version] 0.1.6
[Issue Type] Debug

Change-Id: I813d9d383ae80cf4bba59c12eedc65720db9868b
Signed-off-by: Sangchul Lee <sc11.lee@samsung.com>

Add to build source elements by media source type and link it with webrtcbin

Source type selection bug in webrtc_test is also fixed.

[Version] 0.1.5
[Issue Type] Implementation

Change-Id: I513e1524190f72de88fe2dc50d0fb0ec0c5f0200
Signed-off-by: Sangchul Lee <sc11.lee@samsung.com>

Add infrastructure for adding/removing media source

g_hash_table is used to manage source elements.

[Version] 0.1.4
[Issue Type] Implementation

Change-Id: Ifcf131c61cb48ec284d36f5765afefab9def1901
Signed-off-by: Sangchul Lee <sc11.lee@samsung.com>

Add the basic state change logic

[Version] 0.1.3
[Issue Type] Implementation

Change-Id: Ib2ecbfde9b7791753c8c2f56c34bbda7ed8dd616
Signed-off-by: Sangchul Lee <sc11.lee@samsung.com>

Add webrtcbin element to pipeline and add _gst_destroy_pipeline() sub-function

[Version] 0.1.2
[Issue Type] Improvement

Change-Id: I324a02b04453eb9dfebe4105241e55036ee14c64
Signed-off-by: Sangchul Lee <sc11.lee@samsung.com>

Add initial APIs and test application

[Version] 0.1.1
[Issue Type] Initial code

Change-Id: I398b849a97e7d88d0569ee74385754c59264d768
Signed-off-by: Sangchul Lee <sc11.lee@samsung.com>

Initial empty repository