Removing WebRTC Java API

It's not used any longer.

Was added in https://codereview.chromium.org/551793003/ as temporary solution to use WebRTC from android service.

In following CLs we've moved to native API:
https://codereview.chromium.org/704613003
https://codereview.chromium.org/716433003
https://codereview.chromium.org/719043002
https://codereview.chromium.org/734313002

There is no plan to use Java API for DevTools bridge again.

BUG=383418

Review URL: https://codereview.chromium.org/982563002

Cr-Commit-Position: refs/heads/master@{#319106}

third_party/libjingle/BUILD.gn

@@ -545,42 +545,5 @@ if (enable_webrtc) {
       "//third_party/webrtc/voice_engine",
     ]
   }
-
-  if (is_android) {
-    import("//build/config/android/rules.gni")
-    source_set("libjingle_peerconnection_so") {
-      sources = [
-        "source/talk/app/webrtc/java/jni/peerconnection_jni.cc",
-      ]
-      deps = [
-        ":libjingle_webrtc",
-        ":libpeerconnection",
-      ]
-    }
-
-    android_library("libjingle_peerconnection_java") {
-      java_files = [
-        "source/talk/app/webrtc/java/src/org/webrtc/AudioSource.java",
-        "source/talk/app/webrtc/java/src/org/webrtc/AudioTrack.java",
-        "source/talk/app/webrtc/java/src/org/webrtc/DataChannel.java",
-        "source/talk/app/webrtc/java/src/org/webrtc/IceCandidate.java",
-        "source/talk/app/webrtc/java/src/org/webrtc/Logging.java",
-        "source/talk/app/webrtc/java/src/org/webrtc/MediaConstraints.java",
-        "source/talk/app/webrtc/java/src/org/webrtc/MediaSource.java",
-        "source/talk/app/webrtc/java/src/org/webrtc/MediaStream.java",
-        "source/talk/app/webrtc/java/src/org/webrtc/MediaStreamTrack.java",
-        "source/talk/app/webrtc/java/src/org/webrtc/PeerConnectionFactory.java",
-        "source/talk/app/webrtc/java/src/org/webrtc/PeerConnection.java",
-        "source/talk/app/webrtc/java/src/org/webrtc/SdpObserver.java",
-        "source/talk/app/webrtc/java/src/org/webrtc/StatsObserver.java",
-        "source/talk/app/webrtc/java/src/org/webrtc/StatsReport.java",
-        "source/talk/app/webrtc/java/src/org/webrtc/SessionDescription.java",
-        "source/talk/app/webrtc/java/src/org/webrtc/VideoCapturer.java",
-        "source/talk/app/webrtc/java/src/org/webrtc/VideoRenderer.java",
-        "source/talk/app/webrtc/java/src/org/webrtc/VideoSource.java",
-        "source/talk/app/webrtc/java/src/org/webrtc/VideoTrack.java",
-      ]
-    }
-  }
 }  # enable_webrtc
 # TODO(GYP): Port libjingle.gyp's enable_webrtc condition block.

third_party/libjingle/libjingle.gyp

@@ -645,34 +645,5 @@
         },  # target libpeerconnection
       ],
     }],
-    ['enable_webrtc==1 and OS=="android" and "<(libpeer_target_type)"=="static_library"', {
-      'targets': [
-        {
-          # GN version: //third_party/libjingle:libjingle_peerconnection_so
-          'target_name': 'libjingle_peerconnection_so',
-          'type': 'shared_library',
-          'dependencies': [
-            '<(DEPTH)/third_party/icu/icu.gyp:icuuc',
-            'libjingle_webrtc',
-            'libpeerconnection',
-          ],
-          'sources': [
-            '<(libjingle_source)/talk/app/webrtc/java/jni/peerconnection_jni.cc',
-          ],
-        },
-        {
-          # GN version: //third_party/libjingle:libjingle_peerconnection_java
-          'target_name': 'libjingle_peerconnection_javalib',
-          'type': 'none',
-          'variables': {
-            'java_in_dir': '<(libjingle_source)/talk/app/webrtc/java',
-          },
-          'dependencies': [
-            'libjingle_peerconnection_so',
-          ],
-          'includes': [ '../../build/java.gypi' ],
-        },
-      ],
-    }],
   ],
 }