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_transport_fake.cc b/buffet/http_transport_fake.cc
index 782404a..0e7dfc5 100644
--- a/buffet/http_transport_fake.cc
+++ b/buffet/http_transport_fake.cc
@@ -16,7 +16,7 @@
 #include "buffet/mime_utils.h"
 #include "buffet/url_utils.h"
 
-namespace chromeos {
+namespace buffet {
 
 using http::fake::Transport;
 using http::fake::ServerRequestResponseBase;
@@ -257,4 +257,4 @@
   return std::string();
 }
 
-}  // namespace chromeos
+}  // namespace buffet