Remove GRPCChannel-initWithHost to simplify implementation

src/objective-c/GRPCClient/private/GRPCChannel.h

@@ -43,7 +43,6 @@
 // Convenience constructor to allow for reuse of connections.
 + (instancetype)channelToHost:(NSString *)host;
 
-- (instancetype)initWithHost:(NSString *)host NS_DESIGNATED_INITIALIZER;
 - (instancetype)initWithChannel:(grpc_channel *)unmanagedChannel
                        hostName:(NSString *)hostName NS_DESIGNATED_INITIALIZER;
 

src/objective-c/GRPCClient/private/GRPCChannel.m

@@ -54,17 +54,13 @@
   });
   GRPCChannel *channel = channelCache[host];
   if (!channel) {
-    channel = [[self alloc] initWithHost:host];
+    channel = [self uncachedChannelToHost:host];
     channelCache[host] = channel;
   }
   return channel;
 }
 
-- (instancetype)init {
-  return [self initWithHost:nil];
-}
-
-- (instancetype)initWithHost:(NSString *)host {
++ (instancetype)uncachedChannelToHost:(NSString *)host {
   if (![host rangeOfString:@"://"].length) {
     // No scheme provided; assume https.
     host = [@"https://" stringByAppendingString:host];
@@ -86,6 +82,10 @@
   return nil; // silence warning.
 }
 
+- (instancetype)init {
+  return [self initWithChannel:NULL hostName:nil];
+}
+
 - (instancetype)initWithChannel:(struct grpc_channel *)unmanagedChannel
                        hostName:(NSString *)hostName {
   if (!unmanagedChannel || !hostName) {
@@ -113,12 +113,8 @@
 }
 
 - (void)dealloc {
-  // _unmanagedChannel is NULL when deallocating an object of the base class (because the
-  // initializer returns a different object).
-  if (_unmanagedChannel) {
   // TODO(jcanizales): Be sure to add a test with a server that closes the connection prematurely,
   // as in the past that made this call to crash.
   grpc_channel_destroy(_unmanagedChannel);
-  }
 }
 @end

src/objective-c/GRPCClient/private/GRPCSecureChannel.h

@@ -34,5 +34,5 @@
 #import "GRPCChannel.h"
 
 @interface GRPCSecureChannel : GRPCChannel
-
+- (instancetype)initWithHost:(NSString *)host NS_DESIGNATED_INITIALIZER;
 @end

src/objective-c/GRPCClient/private/GRPCUnsecuredChannel.h

@@ -34,5 +34,5 @@
 #import "GRPCChannel.h"
 
 @interface GRPCUnsecuredChannel : GRPCChannel
-
+- (instancetype)initWithHost:(NSString *)host NS_DESIGNATED_INITIALIZER;
 @end