Don't submit frames with no render passes in cc tests

cc/test/compositor_frame_helpers.h

Index: cc/test/compositor_frame_helpers.h
diff --git a/cc/test/compositor_frame_helpers.h b/cc/test/compositor_frame_helpers.h
index 1c23b69463025c778e310731aa86d0652b400af1..c60de21ebdfc5f12f3517a87e2b7ce56ea60e5ec 100644
--- a/cc/test/compositor_frame_helpers.h
+++ b/cc/test/compositor_frame_helpers.h
@@ -11,8 +11,13 @@ class CompositorFrame;
 
 namespace test {
 
+// Creates a valid CompositorFrame.
 CompositorFrame MakeCompositorFrame();
 
+// Creates a CompositorFrame that will be valid once its render_pass_list is
+// initialized.
+CompositorFrame MakeEmptyCompositorFrame();
+
 }  // namespace test
 }  // namespace cc