Revert of 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 448b2e7221a527e386fa5fd61582843c5f6745cd..2c619c8464177930e9ca102b3d9d41db25544b56 100644
--- a/content/test/BUILD.gn
+++ b/content/test/BUILD.gn
@@ -337,6 +337,15 @@
     resource_dirs = [ "//content/shell/android/browsertests_apk/res" ]
     custom_package = "org.chromium.content_browsertests_apk"
   }
+}
+
+# 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") {
@@ -551,6 +560,15 @@
   }
 }
 
+# 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,
@@ -816,6 +834,15 @@
   }
 }
 
+# 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",