Updates channel credentials

- switches credentials to channel credentials
- removes usages of other credentials classes that would are not
  currently used in the ruby surface
diff --git a/src/ruby/ext/grpc/rb_channel.c b/src/ruby/ext/grpc/rb_channel.c
index 90afdc3..1dcc99d 100644
--- a/src/ruby/ext/grpc/rb_channel.c
+++ b/src/ruby/ext/grpc/rb_channel.c
@@ -41,8 +41,8 @@
 #include "rb_grpc.h"
 #include "rb_call.h"
 #include "rb_channel_args.h"
+#include "rb_channel_credentials.h"
 #include "rb_completion_queue.h"
-#include "rb_credentials.h"
 #include "rb_server.h"
 
 /* id_channel is the name of the hidden ivar that preserves a reference to the
@@ -134,8 +134,8 @@
   VALUE credentials = Qnil;
   VALUE target = Qnil;
   grpc_rb_channel *wrapper = NULL;
-  grpc_credentials *creds = NULL;
   grpc_channel *ch = NULL;
+  grpc_channel_credentials *creds = NULL;
   char *target_chars = NULL;
   grpc_channel_args args;
   MEMZERO(&args, grpc_channel_args, 1);
@@ -149,7 +149,7 @@
   if (credentials == Qnil) {
     ch = grpc_insecure_channel_create(target_chars, &args, NULL);
   } else {
-    creds = grpc_rb_get_wrapped_credentials(credentials);
+    creds = grpc_rb_get_wrapped_channel_credentials(credentials);
     ch = grpc_secure_channel_create(creds, target_chars, &args, NULL);
   }
   if (args.args != NULL) {
diff --git a/src/ruby/ext/grpc/rb_channel_credentials.c b/src/ruby/ext/grpc/rb_channel_credentials.c
new file mode 100644
index 0000000..b7fda28
--- /dev/null
+++ b/src/ruby/ext/grpc/rb_channel_credentials.c
@@ -0,0 +1,225 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "rb_channel_credentials.h"
+
+#include <ruby/ruby.h>
+
+#include <grpc/grpc.h>
+#include <grpc/grpc_security.h>
+
+#include "rb_grpc.h"
+
+/* grpc_rb_cChannelCredentials is the ruby class that proxies
+   grpc_channel_credentials. */
+static VALUE grpc_rb_cChannelCredentials = Qnil;
+
+/* grpc_rb_channel_credentials wraps a grpc_channel_credentials.  It provides a
+ * peer ruby object, 'mark' to minimize copying when a credential is
+ * created from ruby. */
+typedef struct grpc_rb_channel_credentials {
+  /* Holder of ruby objects involved in constructing the credentials */
+  VALUE mark;
+
+  /* The actual credentials */
+  grpc_channel_credentials *wrapped;
+} grpc_rb_channel_credentials;
+
+/* Destroys the credentials instances. */
+static void grpc_rb_channel_credentials_free(void *p) {
+  grpc_rb_channel_credentials *wrapper = NULL;
+  if (p == NULL) {
+    return;
+  };
+  wrapper = (grpc_rb_channel_credentials *)p;
+
+  /* Delete the wrapped object if the mark object is Qnil, which indicates that
+   * no other object is the actual owner. */
+  if (wrapper->wrapped != NULL && wrapper->mark == Qnil) {
+    grpc_channel_credentials_release(wrapper->wrapped);
+    wrapper->wrapped = NULL;
+  }
+
+  xfree(p);
+}
+
+/* Protects the mark object from GC */
+static void grpc_rb_channel_credentials_mark(void *p) {
+  grpc_rb_channel_credentials *wrapper = NULL;
+  if (p == NULL) {
+    return;
+  }
+  wrapper = (grpc_rb_channel_credentials *)p;
+
+  /* If it's not already cleaned up, mark the mark object */
+  if (wrapper->mark != Qnil) {
+    rb_gc_mark(wrapper->mark);
+  }
+}
+
+static rb_data_type_t grpc_rb_channel_credentials_data_type = {
+    "grpc_channel_credentials",
+    {grpc_rb_channel_credentials_mark, grpc_rb_channel_credentials_free,
+     GRPC_RB_MEMSIZE_UNAVAILABLE, {NULL, NULL}},
+    NULL,
+    NULL,
+    RUBY_TYPED_FREE_IMMEDIATELY};
+
+/* Allocates ChannelCredential instances.
+   Provides safe initial defaults for the instance fields. */
+static VALUE grpc_rb_channel_credentials_alloc(VALUE cls) {
+  grpc_rb_channel_credentials *wrapper = ALLOC(grpc_rb_channel_credentials);
+  wrapper->wrapped = NULL;
+  wrapper->mark = Qnil;
+  return TypedData_Wrap_Struct(cls, &grpc_rb_channel_credentials_data_type, wrapper);
+}
+
+/* Clones ChannelCredentials instances.
+   Gives ChannelCredentials a consistent implementation of Ruby's object copy/dup
+   protocol. */
+static VALUE grpc_rb_channel_credentials_init_copy(VALUE copy, VALUE orig) {
+  grpc_rb_channel_credentials *orig_cred = NULL;
+  grpc_rb_channel_credentials *copy_cred = NULL;
+
+  if (copy == orig) {
+    return copy;
+  }
+
+  /* Raise an error if orig is not a credentials object or a subclass. */
+  if (TYPE(orig) != T_DATA ||
+      RDATA(orig)->dfree != (RUBY_DATA_FUNC)grpc_rb_channel_credentials_free) {
+    rb_raise(rb_eTypeError, "not a %s",
+             rb_obj_classname(grpc_rb_cChannelCredentials));
+  }
+
+  TypedData_Get_Struct(orig, grpc_rb_channel_credentials,
+                       &grpc_rb_channel_credentials_data_type, orig_cred);
+  TypedData_Get_Struct(copy, grpc_rb_channel_credentials,
+                       &grpc_rb_channel_credentials_data_type, copy_cred);
+
+  /* use ruby's MEMCPY to make a byte-for-byte copy of the credentials
+   * wrapper object. */
+  MEMCPY(copy_cred, orig_cred, grpc_rb_channel_credentials, 1);
+  return copy;
+}
+
+
+/* The attribute used on the mark object to hold the pem_root_certs. */
+static ID id_pem_root_certs;
+
+/* The attribute used on the mark object to hold the pem_private_key. */
+static ID id_pem_private_key;
+
+/* The attribute used on the mark object to hold the pem_private_key. */
+static ID id_pem_cert_chain;
+
+/*
+  call-seq:
+    creds1 = Credentials.new(pem_root_certs)
+    ...
+    creds2 = Credentials.new(pem_root_certs, pem_private_key,
+                             pem_cert_chain)
+    pem_root_certs: (required) PEM encoding of the server root certificate
+    pem_private_key: (optional) PEM encoding of the client's private key
+    pem_cert_chain: (optional) PEM encoding of the client's cert chain
+    Initializes Credential instances. */
+static VALUE grpc_rb_channel_credentials_init(int argc, VALUE *argv, VALUE self) {
+  VALUE pem_root_certs = Qnil;
+  VALUE pem_private_key = Qnil;
+  VALUE pem_cert_chain = Qnil;
+  grpc_rb_channel_credentials *wrapper = NULL;
+  grpc_channel_credentials *creds = NULL;
+  grpc_ssl_pem_key_cert_pair key_cert_pair;
+  MEMZERO(&key_cert_pair, grpc_ssl_pem_key_cert_pair, 1);
+  /* TODO: Remove mandatory arg when we support default roots. */
+  /* "12" == 1 mandatory arg, 2 (credentials) is optional */
+  rb_scan_args(argc, argv, "12", &pem_root_certs, &pem_private_key,
+               &pem_cert_chain);
+
+  TypedData_Get_Struct(self, grpc_rb_channel_credentials,
+                       &grpc_rb_channel_credentials_data_type, wrapper);
+  if (pem_root_certs == Qnil) {
+    rb_raise(rb_eRuntimeError,
+             "could not create a credential: nil pem_root_certs");
+    return Qnil;
+  }
+  if (pem_private_key == Qnil && pem_cert_chain == Qnil) {
+    creds =
+        grpc_ssl_credentials_create(RSTRING_PTR(pem_root_certs), NULL, NULL);
+  } else {
+    key_cert_pair.private_key = RSTRING_PTR(pem_private_key);
+    key_cert_pair.cert_chain = RSTRING_PTR(pem_cert_chain);
+    creds = grpc_ssl_credentials_create(RSTRING_PTR(pem_root_certs),
+                                        &key_cert_pair, NULL);
+  }
+  if (creds == NULL) {
+    rb_raise(rb_eRuntimeError, "could not create a credentials, not sure why");
+    return Qnil;
+  }
+  wrapper->wrapped = creds;
+
+  /* Add the input objects as hidden fields to preserve them. */
+  rb_ivar_set(self, id_pem_cert_chain, pem_cert_chain);
+  rb_ivar_set(self, id_pem_private_key, pem_private_key);
+  rb_ivar_set(self, id_pem_root_certs, pem_root_certs);
+
+  return self;
+}
+
+void Init_grpc_channel_credentials() {
+  grpc_rb_cChannelCredentials =
+      rb_define_class_under(grpc_rb_mGrpcCore, "ChannelCredentials", rb_cObject);
+
+  /* Allocates an object managed by the ruby runtime */
+  rb_define_alloc_func(grpc_rb_cChannelCredentials,
+                       grpc_rb_channel_credentials_alloc);
+
+  /* Provides a ruby constructor and support for dup/clone. */
+  rb_define_method(grpc_rb_cChannelCredentials, "initialize",
+                   grpc_rb_channel_credentials_init, -1);
+  rb_define_method(grpc_rb_cChannelCredentials, "initialize_copy",
+                   grpc_rb_channel_credentials_init_copy, 1);
+
+  id_pem_cert_chain = rb_intern("__pem_cert_chain");
+  id_pem_private_key = rb_intern("__pem_private_key");
+  id_pem_root_certs = rb_intern("__pem_root_certs");
+}
+
+/* Gets the wrapped grpc_channel_credentials from the ruby wrapper */
+grpc_channel_credentials *grpc_rb_get_wrapped_channel_credentials(VALUE v) {
+  grpc_rb_channel_credentials *wrapper = NULL;
+  TypedData_Get_Struct(v, grpc_rb_channel_credentials,
+                       &grpc_rb_channel_credentials_data_type,
+                       wrapper);
+  return wrapper->wrapped;
+}
diff --git a/src/ruby/ext/grpc/rb_credentials.h b/src/ruby/ext/grpc/rb_channel_credentials.h
similarity index 91%
rename from src/ruby/ext/grpc/rb_credentials.h
rename to src/ruby/ext/grpc/rb_channel_credentials.h
index 840f7d5..15229de 100644
--- a/src/ruby/ext/grpc/rb_credentials.h
+++ b/src/ruby/ext/grpc/rb_channel_credentials.h
@@ -38,10 +38,10 @@
 
 #include <grpc/grpc_security.h>
 
-/* Initializes the ruby Credentials class. */
-void Init_grpc_credentials();
+/* Initializes the ruby ChannelCredentials class. */
+void Init_grpc_channel_credentials();
 
 /* Gets the wrapped credentials from the ruby wrapper */
-grpc_credentials* grpc_rb_get_wrapped_credentials(VALUE v);
+grpc_channel_credentials* grpc_rb_get_wrapped_channel_credentials(VALUE v);
 
 #endif /* GRPC_RB_CREDENTIALS_H_ */
diff --git a/src/ruby/ext/grpc/rb_credentials.c b/src/ruby/ext/grpc/rb_credentials.c
deleted file mode 100644
index ae757f6..0000000
--- a/src/ruby/ext/grpc/rb_credentials.c
+++ /dev/null
@@ -1,294 +0,0 @@
-/*
- *
- * Copyright 2015, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
-
-#include "rb_credentials.h"
-
-#include <ruby/ruby.h>
-
-#include <grpc/grpc.h>
-#include <grpc/grpc_security.h>
-
-#include "rb_grpc.h"
-
-/* grpc_rb_cCredentials is the ruby class that proxies grpc_credentials. */
-static VALUE grpc_rb_cCredentials = Qnil;
-
-/* grpc_rb_credentials wraps a grpc_credentials.  It provides a
- * peer ruby object, 'mark' to minimize copying when a credential is
- * created from ruby. */
-typedef struct grpc_rb_credentials {
-  /* Holder of ruby objects involved in constructing the credentials */
-  VALUE mark;
-
-  /* The actual credentials */
-  grpc_credentials *wrapped;
-} grpc_rb_credentials;
-
-/* Destroys the credentials instances. */
-static void grpc_rb_credentials_free(void *p) {
-  grpc_rb_credentials *wrapper = NULL;
-  if (p == NULL) {
-    return;
-  };
-  wrapper = (grpc_rb_credentials *)p;
-
-  /* Delete the wrapped object if the mark object is Qnil, which indicates that
-   * no other object is the actual owner. */
-  if (wrapper->wrapped != NULL && wrapper->mark == Qnil) {
-    grpc_credentials_release(wrapper->wrapped);
-    wrapper->wrapped = NULL;
-  }
-
-  xfree(p);
-}
-
-/* Protects the mark object from GC */
-static void grpc_rb_credentials_mark(void *p) {
-  grpc_rb_credentials *wrapper = NULL;
-  if (p == NULL) {
-    return;
-  }
-  wrapper = (grpc_rb_credentials *)p;
-
-  /* If it's not already cleaned up, mark the mark object */
-  if (wrapper->mark != Qnil) {
-    rb_gc_mark(wrapper->mark);
-  }
-}
-
-static rb_data_type_t grpc_rb_credentials_data_type = {
-    "grpc_credentials",
-    {grpc_rb_credentials_mark, grpc_rb_credentials_free,
-     GRPC_RB_MEMSIZE_UNAVAILABLE, {NULL, NULL}},
-    NULL,
-    NULL,
-    RUBY_TYPED_FREE_IMMEDIATELY};
-
-/* Allocates Credential instances.
-   Provides safe initial defaults for the instance fields. */
-static VALUE grpc_rb_credentials_alloc(VALUE cls) {
-  grpc_rb_credentials *wrapper = ALLOC(grpc_rb_credentials);
-  wrapper->wrapped = NULL;
-  wrapper->mark = Qnil;
-  return TypedData_Wrap_Struct(cls, &grpc_rb_credentials_data_type, wrapper);
-}
-
-/* Clones Credentials instances.
-   Gives Credentials a consistent implementation of Ruby's object copy/dup
-   protocol. */
-static VALUE grpc_rb_credentials_init_copy(VALUE copy, VALUE orig) {
-  grpc_rb_credentials *orig_cred = NULL;
-  grpc_rb_credentials *copy_cred = NULL;
-
-  if (copy == orig) {
-    return copy;
-  }
-
-  /* Raise an error if orig is not a credentials object or a subclass. */
-  if (TYPE(orig) != T_DATA ||
-      RDATA(orig)->dfree != (RUBY_DATA_FUNC)grpc_rb_credentials_free) {
-    rb_raise(rb_eTypeError, "not a %s", rb_obj_classname(grpc_rb_cCredentials));
-  }
-
-  TypedData_Get_Struct(orig, grpc_rb_credentials,
-                       &grpc_rb_credentials_data_type, orig_cred);
-  TypedData_Get_Struct(copy, grpc_rb_credentials,
-                       &grpc_rb_credentials_data_type, copy_cred);
-
-  /* use ruby's MEMCPY to make a byte-for-byte copy of the credentials
-   * wrapper object. */
-  MEMCPY(copy_cred, orig_cred, grpc_rb_credentials, 1);
-  return copy;
-}
-
-/*
-  call-seq:
-    creds = Credentials.default()
-    Creates the default credential instances. */
-static VALUE grpc_rb_default_credentials_create(VALUE cls) {
-  grpc_rb_credentials *wrapper = ALLOC(grpc_rb_credentials);
-  wrapper->wrapped = grpc_google_default_credentials_create();
-  if (wrapper->wrapped == NULL) {
-    rb_raise(rb_eRuntimeError,
-             "could not create default credentials, not sure why");
-    return Qnil;
-  }
-
-  wrapper->mark = Qnil;
-  return TypedData_Wrap_Struct(cls, &grpc_rb_credentials_data_type, wrapper);
-}
-
-/*
-  call-seq:
-    creds = Credentials.compute_engine()
-    Creates the default credential instances. */
-static VALUE grpc_rb_compute_engine_credentials_create(VALUE cls) {
-  grpc_rb_credentials *wrapper = ALLOC(grpc_rb_credentials);
-  wrapper->wrapped = grpc_google_compute_engine_credentials_create(NULL);
-  if (wrapper->wrapped == NULL) {
-    rb_raise(rb_eRuntimeError,
-             "could not create composite engine credentials, not sure why");
-    return Qnil;
-  }
-
-  wrapper->mark = Qnil;
-  return TypedData_Wrap_Struct(cls, &grpc_rb_credentials_data_type, wrapper);
-}
-
-/*
-  call-seq:
-    creds1 = ...
-    creds2 = ...
-    creds3 = creds1.add(creds2)
-    Creates the default credential instances. */
-static VALUE grpc_rb_composite_credentials_create(VALUE self, VALUE other) {
-  grpc_rb_credentials *self_wrapper = NULL;
-  grpc_rb_credentials *other_wrapper = NULL;
-  grpc_rb_credentials *wrapper = NULL;
-
-  TypedData_Get_Struct(self, grpc_rb_credentials,
-                       &grpc_rb_credentials_data_type, self_wrapper);
-  TypedData_Get_Struct(other, grpc_rb_credentials,
-                       &grpc_rb_credentials_data_type, other_wrapper);
-  wrapper = ALLOC(grpc_rb_credentials);
-  wrapper->wrapped = grpc_composite_credentials_create(
-      self_wrapper->wrapped, other_wrapper->wrapped, NULL);
-  if (wrapper->wrapped == NULL) {
-    rb_raise(rb_eRuntimeError,
-             "could not create composite credentials, not sure why");
-    return Qnil;
-  }
-
-  wrapper->mark = Qnil;
-  return TypedData_Wrap_Struct(grpc_rb_cCredentials,
-                               &grpc_rb_credentials_data_type, wrapper);
-}
-
-/* The attribute used on the mark object to hold the pem_root_certs. */
-static ID id_pem_root_certs;
-
-/* The attribute used on the mark object to hold the pem_private_key. */
-static ID id_pem_private_key;
-
-/* The attribute used on the mark object to hold the pem_private_key. */
-static ID id_pem_cert_chain;
-
-/*
-  call-seq:
-    creds1 = Credentials.new(pem_root_certs)
-    ...
-    creds2 = Credentials.new(pem_root_certs, pem_private_key,
-                             pem_cert_chain)
-    pem_root_certs: (required) PEM encoding of the server root certificate
-    pem_private_key: (optional) PEM encoding of the client's private key
-    pem_cert_chain: (optional) PEM encoding of the client's cert chain
-    Initializes Credential instances. */
-static VALUE grpc_rb_credentials_init(int argc, VALUE *argv, VALUE self) {
-  VALUE pem_root_certs = Qnil;
-  VALUE pem_private_key = Qnil;
-  VALUE pem_cert_chain = Qnil;
-  grpc_rb_credentials *wrapper = NULL;
-  grpc_credentials *creds = NULL;
-  grpc_ssl_pem_key_cert_pair key_cert_pair;
-  MEMZERO(&key_cert_pair, grpc_ssl_pem_key_cert_pair, 1);
-  /* TODO: Remove mandatory arg when we support default roots. */
-  /* "12" == 1 mandatory arg, 2 (credentials) is optional */
-  rb_scan_args(argc, argv, "12", &pem_root_certs, &pem_private_key,
-               &pem_cert_chain);
-
-  TypedData_Get_Struct(self, grpc_rb_credentials,
-                       &grpc_rb_credentials_data_type, wrapper);
-  if (pem_root_certs == Qnil) {
-    rb_raise(rb_eRuntimeError,
-             "could not create a credential: nil pem_root_certs");
-    return Qnil;
-  }
-  if (pem_private_key == Qnil && pem_cert_chain == Qnil) {
-    creds =
-        grpc_ssl_credentials_create(RSTRING_PTR(pem_root_certs), NULL, NULL);
-  } else {
-    key_cert_pair.private_key = RSTRING_PTR(pem_private_key);
-    key_cert_pair.cert_chain = RSTRING_PTR(pem_cert_chain);
-    creds = grpc_ssl_credentials_create(RSTRING_PTR(pem_root_certs),
-                                        &key_cert_pair, NULL);
-  }
-  if (creds == NULL) {
-    rb_raise(rb_eRuntimeError, "could not create a credentials, not sure why");
-    return Qnil;
-  }
-  wrapper->wrapped = creds;
-
-  /* Add the input objects as hidden fields to preserve them. */
-  rb_ivar_set(self, id_pem_cert_chain, pem_cert_chain);
-  rb_ivar_set(self, id_pem_private_key, pem_private_key);
-  rb_ivar_set(self, id_pem_root_certs, pem_root_certs);
-
-  return self;
-}
-
-void Init_grpc_credentials() {
-  grpc_rb_cCredentials =
-      rb_define_class_under(grpc_rb_mGrpcCore, "Credentials", rb_cObject);
-
-  /* Allocates an object managed by the ruby runtime */
-  rb_define_alloc_func(grpc_rb_cCredentials, grpc_rb_credentials_alloc);
-
-  /* Provides a ruby constructor and support for dup/clone. */
-  rb_define_method(grpc_rb_cCredentials, "initialize", grpc_rb_credentials_init,
-                   -1);
-  rb_define_method(grpc_rb_cCredentials, "initialize_copy",
-                   grpc_rb_credentials_init_copy, 1);
-
-  /* Provide static funcs that create new special instances. */
-  rb_define_singleton_method(grpc_rb_cCredentials, "default",
-                             grpc_rb_default_credentials_create, 0);
-
-  rb_define_singleton_method(grpc_rb_cCredentials, "compute_engine",
-                             grpc_rb_compute_engine_credentials_create, 0);
-
-  /* Provide other methods. */
-  rb_define_method(grpc_rb_cCredentials, "compose",
-                   grpc_rb_composite_credentials_create, 1);
-
-  id_pem_cert_chain = rb_intern("__pem_cert_chain");
-  id_pem_private_key = rb_intern("__pem_private_key");
-  id_pem_root_certs = rb_intern("__pem_root_certs");
-}
-
-/* Gets the wrapped grpc_credentials from the ruby wrapper */
-grpc_credentials *grpc_rb_get_wrapped_credentials(VALUE v) {
-  grpc_rb_credentials *wrapper = NULL;
-  TypedData_Get_Struct(v, grpc_rb_credentials, &grpc_rb_credentials_data_type,
-                       wrapper);
-  return wrapper->wrapped;
-}
diff --git a/src/ruby/ext/grpc/rb_grpc.c b/src/ruby/ext/grpc/rb_grpc.c
index 327fd1a..bbbeede 100644
--- a/src/ruby/ext/grpc/rb_grpc.c
+++ b/src/ruby/ext/grpc/rb_grpc.c
@@ -42,9 +42,9 @@
 #include <grpc/support/time.h>
 #include "rb_call.h"
 #include "rb_channel.h"
+#include "rb_channel_credentials.h"
 #include "rb_completion_queue.h"
 #include "rb_server.h"
-#include "rb_credentials.h"
 #include "rb_server_credentials.h"
 
 static VALUE grpc_rb_cTimeVal = Qnil;
@@ -300,7 +300,7 @@
   Init_grpc_channel();
   Init_grpc_completion_queue();
   Init_grpc_call();
-  Init_grpc_credentials();
+  Init_grpc_channel_credentials();
   Init_grpc_server();
   Init_grpc_server_credentials();
   Init_grpc_status_codes();