Revert of [Chromoting] Add DataChannelManager to manage optional inco…

…ming data channels (patchset chromium#8 id:320001 of https://codereview.chromium.org/2907073003/ )

Reason for revert:
New unittests are failing:

https://luci-logdog.appspot.com/v/?s=chromium%2Fbb%2Fchromium.mac%2FMac10.10_Tests%2F19251%2F%2B%2Frecipes%2Fsteps%2Fremoting_unittests_on_Mac-10.10%2F0%2Flogs%2FDataChannelManagerTest.FullMatchWithAsynchronousPipe%2F0

Original issue's description:
> [Chromoting] Add DataChannelManager to manage optional incoming data channels
>
> DataChannelManager manages a set of factory functions to create
> DataChannelHandler instances to handle named data channels. So once the peer
> creates a new data channel, DataChannelManager can automatically handle it.
> Lifetime of a DataChannelHandler is consistent with the MessagePipe it received:
> it deletes itself once the MessagePipe is closed.
>
> BUG=650926
>
> Review-Url: https://codereview.chromium.org/2907073003
> Cr-Commit-Position: refs/heads/master@{#478442}
> Committed: https://chromium.googlesource.com/chromium/src/+/4a15f818c5fdbd1e2c44bf102047ecd9b2c166e2

TBR=sergeyu@chromium.org,joedow@chromium.org,zijiehe@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=650926

Review-Url: https://codereview.chromium.org/2928133005
Cr-Commit-Position: refs/heads/master@{#478485}

remoting/proto/BUILD.gn

@@ -19,7 +19,6 @@ proto_library("proto") {
     "internal.proto",
     "mux.proto",
     "process_stats.proto",
-    "test.proto",
     "video.proto",
     "video_stats.proto",
   ]

remoting/protocol/BUILD.gn

@@ -49,8 +49,6 @@ static_library("protocol") {
     "content_description.cc",
     "content_description.h",
     "datagram_channel_factory.h",
-    "data_channel_manager.cc",
-    "data_channel_manager.h",
     "errors.cc",
     "errors.h",
     "frame_consumer.h",
@@ -106,8 +104,6 @@ static_library("protocol") {
     "monitored_video_stub.h",
     "mouse_input_filter.cc",
     "mouse_input_filter.h",
-    "named_message_pipe_handler.cc",
-    "named_message_pipe_handler.h",
     "negotiating_authenticator_base.cc",
     "negotiating_authenticator_base.h",
     "negotiating_client_authenticator.cc",
@@ -270,10 +266,6 @@ static_library("test_support") {
     "fake_connection_to_host.h",
     "fake_datagram_socket.cc",
     "fake_datagram_socket.h",
-    "fake_message_pipe.cc",
-    "fake_message_pipe.h",
-    "fake_message_pipe_wrapper.cc",
-    "fake_message_pipe_wrapper.h",
     "fake_session.cc",
     "fake_session.h",
     "fake_stream_socket.cc",
@@ -317,7 +309,6 @@ source_set("unit_tests") {
     "connection_tester.cc",
     "connection_tester.h",
     "content_description_unittest.cc",
-    "data_channel_manager_unittest.cc",
     "http_ice_config_request_unittest.cc",
     "ice_config_unittest.cc",
     "ice_transport_unittest.cc",