Changed previews component to be a layered component.

components/previews/core/previews_experiments.h

Index: components/previews/core/previews_experiments.h
diff --git a/components/previews/previews_experiments.h b/components/previews/core/previews_experiments.h
similarity index 78%
rename from components/previews/previews_experiments.h
rename to components/previews/core/previews_experiments.h
index 7fff9c476a9b0e332ae4c29b02335781ac4f72a2..258f436e27fcf903535548e730772d73312a7ebe 100644
--- a/components/previews/previews_experiments.h
+++ b/components/previews/core/previews_experiments.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef COMPONENTS_PREVIEWS_PREVIEWS_EXPERIMENTS_H_
-#define COMPONENTS_PREVIEWS_PREVIEWS_EXPERIMENTS_H_
+#ifndef COMPONENTS_PREVIEWS_CORE_PREVIEWS_EXPERIMENTS_H_
+#define COMPONENTS_PREVIEWS_CORE_PREVIEWS_EXPERIMENTS_H_
 
 namespace previews {
 
@@ -20,4 +20,4 @@ bool EnableOfflinePreviewsForTesting();
 
 }  // namespace previews
 
-#endif  // COMPONENTS_PREVIEWS_PREVIEWS_EXPERIMENTS_H_
+#endif  // COMPONENTS_PREVIEWS_CORE_PREVIEWS_EXPERIMENTS_H_