buffet: Remove 'chromeos' namespace and move everything to buffet NS

As discussed, moved all the classes out of chromeos namespace into
'buffet.

Also fixed a number of cpplint's warnings.

BUG=None
TEST=Everything still compiles and unit tests succeed.

Change-Id: Ide864acb2504627404966727f66d353af60e531d
Reviewed-on: https://chromium-review.googlesource.com/198971
Reviewed-by: Christopher Wiley <wiley@chromium.org>
Commit-Queue: Alex Vakulenko <avakulenko@chromium.org>
Tested-by: Alex Vakulenko <avakulenko@chromium.org>
diff --git a/buffet/http_utils.h b/buffet/http_utils.h
index e44b378..20e255b 100644
--- a/buffet/http_utils.h
+++ b/buffet/http_utils.h
@@ -17,7 +17,7 @@
   class DictionaryValue;
 }  // namespace base
 
-namespace chromeos {
+namespace buffet {
 namespace http {
 
 extern const char kErrorDomainJSON[];
@@ -176,6 +176,6 @@
     const Response* response, int* status_code, ErrorPtr* error);
 
 }  // namespace http
-}  // namespace chromeos
+}  // namespace buffet
 
 #endif  // BUFFET_HTTP_UTILS_H_