Move gn _run target generation into test().

content/test/BUILD.gn

Index: content/test/BUILD.gn
diff --git a/content/test/BUILD.gn b/content/test/BUILD.gn
index 2c619c8464177930e9ca102b3d9d41db25544b56..448b2e7221a527e386fa5fd61582843c5f6745cd 100644
--- a/content/test/BUILD.gn
+++ b/content/test/BUILD.gn
@@ -339,15 +339,6 @@ if (is_android) {
   }
 }
 
-# TODO(GYP): Delete this after we've converted everything to GN.
-# The _run targets exist only for compatibility w/ GYP.
-group("content_browsertests_run") {
-  testonly = true
-  deps = [
-    ":content_browsertests",
-  ]
-}
-
 test("content_browsertests") {
   sources = rebase_path(content_tests_gypi_values.content_browsertests_sources,
                         ".",
@@ -560,15 +551,6 @@ test("content_browsertests") {
   }
 }
 
-# TODO(GYP): Delete this after we've converted everything to GN.
-# The _run targets exist only for compatibility w/ GYP.
-group("content_unittests_run") {
-  testonly = true
-  deps = [
-    ":content_unittests",
-  ]
-}
-
 test("content_unittests") {
   defines = []
   sources = rebase_path(content_tests_gypi_values.content_unittests_sources,
@@ -834,15 +816,6 @@ test("content_perftests") {
   }
 }
 
-# TODO(GYP): Delete this after we've converted everything to GN.
-# The _run targets exist only for compatibility w/ GYP.
-group("content_gl_tests_run") {
-  testonly = true
-  deps = [
-    ":content_gl_tests",
-  ]
-}
-
 test("content_gl_tests") {
   sources = [
     "../common/gpu/client/gl_helper_unittest.cc",