[Cronet] make HttpCacheType enum more comfortative to Obj-C style.

components/cronet/ios/Cronet.mm

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "components/cronet/ios/Cronet.h"
 
 #include <memory>
 
 #include "base/lazy_instance.h"
 #include "base/logging.h"
@@ skipping 143 matching lines @@
   [self checkNotStarted];
   gUserAgent = userAgent;
   gUserAgentPartial = partial;
 }
 
 + (void)setSslKeyLogFileName:(NSString*)sslKeyLogFileName {
   [self checkNotStarted];
   gSslKeyLogFileName = sslKeyLogFileName;
 }
 
-+ (void)setHttpCacheType:(HttpCacheType)httpCacheType {
++ (void)setHttpCacheType:(CRNHttpCacheType)httpCacheType {
   [self checkNotStarted];
   switch (httpCacheType) {
-    case DISABLED:
+    case CRNHttpCacheTypeDisabled:
       gHttpCache = cronet::URLRequestContextConfig::HttpCacheType::DISABLED;
       break;
-    case DISK:
+    case CRNHttpCacheTypeDisk:
       gHttpCache = cronet::URLRequestContextConfig::HttpCacheType::DISK;
       break;
-    case MEMORY:
+    case CRNHttpCacheTypeMemory:
       gHttpCache = cronet::URLRequestContextConfig::HttpCacheType::MEMORY;
       break;
     default:
       DCHECK(NO) << "Invalid HTTP cache type: " << httpCacheType;
   }
 }
 
 + (void)setRequestFilterBlock:(RequestFilterBlock)block {
   if (gHttpProtocolHandlerDelegate.get())
     gHttpProtocolHandlerDelegate.get()->SetRequestFilterBlock(block);
@@ skipping 126 matching lines @@
       base::SysNSStringToUTF8(hostResolverRulesForTesting));
 }
 
 // This is a non-public dummy method that prevents the linker from stripping out
 // the otherwise non-referenced methods from 'bidirectional_stream.cc'.
 + (void)preventStrippingCronetBidirectionalStream {
   bidirectional_stream_create(NULL, 0, 0);
 }
 
 @end