Add display_compositor unittests into components_unittests

components/display_compositor/gl_helper_unittest.cc

Index: components/display_compositor/gl_helper_unittest.cc
diff --git a/components/display_compositor/gl_helper_unittest.cc b/components/display_compositor/gl_helper_unittest.cc
index abd2d5136968af9e89d310ec27ff7b32b92f6ff2..5800c970cc51fbc18ed3f471167431dd6ea53bef 100644
--- a/components/display_compositor/gl_helper_unittest.cc
+++ b/components/display_compositor/gl_helper_unittest.cc
@@ -1263,6 +1263,7 @@ class GLHelperTest : public testing::Test {
   std::unique_ptr<display_compositor::GLHelper> helper_;
   std::unique_ptr<display_compositor::GLHelperScaling> helper_scaling_;
   std::deque<GLHelperScaling::ScaleOp> x_ops_, y_ops_;
+  base::MessageLoop message_loop_;
 };
 
 class GLHelperPixelTest : public GLHelperTest {