Turn components/crash into a layered component.

components/crash/content/app/crash_keys_win.h

Index: components/crash/content/app/crash_keys_win.h
diff --git a/components/crash/app/crash_keys_win.h b/components/crash/content/app/crash_keys_win.h
similarity index 94%
rename from components/crash/app/crash_keys_win.h
rename to components/crash/content/app/crash_keys_win.h
index d61ea2c5765e68f1febee44f77593f31c898c975..870de77af3357ec9ec783b547edabef4d743aeac 100644
--- a/components/crash/app/crash_keys_win.h
+++ b/components/crash/content/app/crash_keys_win.h
@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#ifndef COMPONENTS_CRASH_CONTENT_APP_CRASH_KEYS_WIN_H_
+#define COMPONENTS_CRASH_CONTENT_APP_CRASH_KEYS_WIN_H_
+
 #include <map>
 #include <string>
 #include <vector>
@@ -80,3 +83,5 @@ class CrashKeysWin {
 };
 
 }  // namespace breakpad
+
+#endif  // COMPONENTS_CRASH_CONTENT_APP_CRASH_KEYS_WIN_H_