Set rtc_link_task_queue_impl = false and link in task_queue.cc explic…

…itly.

Bug: webrtc:8166
Change-Id: I83f4adb45f66a90db179f229e165419a6d3307c1
Reviewed-on: https://chromium-review.googlesource.com/681814
Reviewed-by: Per Kjellander <perkj@chromium.org>
Reviewed-by: Henrik Kjellander <kjellander@chromium.org>
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Commit-Queue: Niels Möller <nisse@chromium.org>
Cr-Commit-Position: refs/heads/master@{#505570}

.gn

@@ -53,6 +53,9 @@ default_args = {
   # TODO(jochen): Remove this. http://crbug.com/v8/5830,
   # http://crbug.com/728583.
   v8_check_microtasks_scopes_consistency = false
+
+  # Don't include webrtc's builtin task queue implementation.
+  rtc_link_task_queue_impl = false
 }
 
 # These are the targets to check headers for by default. The files in targets

third_party/webrtc_overrides/BUILD.gn

@@ -97,6 +97,9 @@ static_library("init_webrtc") {
   public_deps = [
     ":libjingle_webrtc_common",
   ]
+  deps = [
+    ":task_queue_impl",
+  ]
 }
 
 source_set("libjingle_webrtc_common") {
@@ -123,3 +126,12 @@ source_set("libjingle_webrtc_common") {
     "//third_party/webrtc/voice_engine",
   ]
 }
+
+source_set("task_queue_impl") {
+  sources = [
+    "rtc_base/task_queue.cc",
+  ]
+  deps = [
+    "//third_party/webrtc/rtc_base:rtc_task_queue_api",
+  ]
+}