GN: move webrtc/video/ targets from webrtc/BUILD.gn into webrtc/video/BUILD.gn

Move the following targets into webrtc/video/BUILD.gn:
* screenshare_loopback
* video_quality_test
* video_loopback

Add new target 'run_tests' in webrtc/test/BUILD.gn, being used by two
of the above and make then depend on that instead.

BUG=webrtc:6440
NOTRY=True

Review-Url: https://codereview.webrtc.org/2438973002
Cr-Commit-Position: refs/heads/master@{#14735}
diff --git a/webrtc/video/BUILD.gn b/webrtc/video/BUILD.gn
index 863f2f5..c8d32b0 100644
--- a/webrtc/video/BUILD.gn
+++ b/webrtc/video/BUILD.gn
@@ -73,6 +73,71 @@
 }
 
 if (rtc_include_tests) {
+  rtc_source_set("video_quality_test") {
+    testonly = true
+    sources = [
+      "video_quality_test.cc",
+      "video_quality_test.h",
+    ]
+    deps = [
+      "../system_wrappers",
+      "//testing/gtest",
+    ]
+    if (!is_android) {
+      deps += [ "../modules/video_capture:video_capture_internal_impl" ]
+    }
+    if (!build_with_chromium && is_clang) {
+      # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
+      suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
+    }
+  }
+
+  rtc_executable("video_loopback") {
+    testonly = true
+    sources = [
+      "video_loopback.cc",
+    ]
+    deps = [
+      ":video_quality_test",
+      "../system_wrappers:metrics_default",
+      "../test:field_trial",
+      "../test:run_test",
+      "../test:test_common",
+      "../test:test_renderer",
+      "//testing/gmock",
+      "//testing/gtest",
+      "//third_party/gflags",
+    ]
+    if (!build_with_chromium && is_clang) {
+      # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
+      suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
+    }
+  }
+
+  rtc_executable("screenshare_loopback") {
+    testonly = true
+    sources = [
+      "screenshare_loopback.cc",
+    ]
+
+    deps = [
+      ":video_quality_test",
+      "../system_wrappers:metrics_default",
+      "../test:field_trial",
+      "../test:run_test",
+      "../test:test_common",
+      "../test:test_renderer",
+      "//testing/gmock",
+      "//testing/gtest",
+      "//third_party/gflags",
+    ]
+    if (!build_with_chromium && is_clang) {
+      # Suppress warnings from Chrome's Clang plugins.
+      # See http://code.google.com/p/webrtc/issues/detail?id=163 for details.
+      suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
+    }
+  }
+
   # TODO(pbos): Rename test suite.
   rtc_source_set("video_tests") {
     testonly = true