Cleanup blimp/client/core code organization.

blimp/client/core/context/blimp_client_context_impl.h

Index: blimp/client/core/context/blimp_client_context_impl.h
diff --git a/blimp/client/core/blimp_client_context_impl.h b/blimp/client/core/context/blimp_client_context_impl.h
similarity index 96%
rename from blimp/client/core/blimp_client_context_impl.h
rename to blimp/client/core/context/blimp_client_context_impl.h
index 8ee0f2a3027965c1e8dcc8724f157c20b086b2cd..7bb222fc79d3de3a20d956d7085666671734c2cd 100644
--- a/blimp/client/core/blimp_client_context_impl.h
+++ b/blimp/client/core/context/blimp_client_context_impl.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 BLIMP_CLIENT_CORE_BLIMP_CLIENT_CONTEXT_IMPL_H_
-#define BLIMP_CLIENT_CORE_BLIMP_CLIENT_CONTEXT_IMPL_H_
+#ifndef BLIMP_CLIENT_CORE_CONTEXT_BLIMP_CLIENT_CONTEXT_IMPL_H_
+#define BLIMP_CLIENT_CORE_CONTEXT_BLIMP_CLIENT_CONTEXT_IMPL_H_
 
 #include <memory>
 #include <string>
@@ -142,4 +142,4 @@ class BlimpClientContextImpl
 }  // namespace client
 }  // namespace blimp
 
-#endif  // BLIMP_CLIENT_CORE_BLIMP_CLIENT_CONTEXT_IMPL_H_
+#endif  // BLIMP_CLIENT_CORE_CONTEXT_BLIMP_CLIENT_CONTEXT_IMPL_H_