Style guide related feedback fixes.

src/objective-c/GRPCClient/GRPCCall+Cronet.h

@@ -39,9 +39,16 @@
  */
 @interface GRPCCall (Cronet)
 
-+(void)useCronet:(cronet_engine *)cronet_engine;
+/* This method should be called before issuing the first RPC. It should be
+ * called only once. Create an instance of Cronet engine in your app elsewhere
+ * and pass the instance pointer in the cronet_engine parameter. Once set,
+ * all subsequent RPCs will use Cronet transport. The method is not thread
+ * safe.
+ */
+
++(void)useCronetWithEngine:(cronet_engine *)engine;
 
-+(void *)getCronetEngine;
++(cronet_engine *)cronetEngine;
 
 +(BOOL)isUsingCronet;
 

src/objective-c/GRPCClient/GRPCCall+Cronet.m

@@ -33,22 +33,22 @@
 
 #import "GRPCCall+Cronet.h"
 
-static BOOL use_cronet = NO;
-static void *g_cronet_engine;
+static BOOL useCronet = NO;
+static cronet_engine *globalCronetEngine;
 
 @implementation GRPCCall (Cronet)
 
-+ (void)useCronet:(cronet_engine *)cronet_engine {
-  use_cronet = YES;
-  g_cronet_engine = cronet_engine;
++ (void)useCronetWithEngine:(cronet_engine *)engine {
+  useCronet = YES;
+  globalCronetEngine = engine;
 }
 
-+ (void *)getCronetEngine {
-  return g_cronet_engine;
++ (cronet_engine *)cronetEngine {
+  return globalCronetEngine;
 }
 
 + (BOOL)isUsingCronet {
-  return use_cronet;
+  return useCronet;
 }
 
 @end

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

@@ -154,7 +154,7 @@ grpc_channel_args * buildChannelArgs(NSDictionary *dictionary) {
 
 + (GRPCChannel *)secureCronetChannelWithHost:(NSString *)host
                                  channelArgs:(NSDictionary *)channelArgs {
-  void *engine = [GRPCCall getCronetEngine];
+  cronet_engine *engine = [GRPCCall cronetEngine];
   if (!engine) {
     [NSException raise:NSInvalidArgumentException
                 format:@"cronet_engine is NULL. Set it first."];

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

@@ -201,14 +201,14 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (GRPCChannel *)newChannel {
   NSDictionary *args = [self channelArgs];
-  BOOL use_cronet = [GRPCCall isUsingCronet];
+  BOOL useCronet = [GRPCCall isUsingCronet];
   if (_secure) {
       GRPCChannel *channel;
       @synchronized(self) {
         if (_channelCreds == nil) {
           [self setTLSPEMRootCerts:nil withPrivateKey:nil withCertChain:nil error:nil];
         }
-        if (use_cronet) {
+        if (useCronet) {
           channel = [GRPCChannel secureCronetChannelWithHost:_address
                                                  channelArgs:args];
         } else {

src/objective-c/tests/InteropTests.m

@@ -80,7 +80,7 @@
 
 #pragma mark Tests
 
-static cronet_engine *_engine = NULL;
+static cronet_engine *cronetEngine = NULL;
 
 @implementation InteropTests {
   RMTTestService *_service;
@@ -93,12 +93,12 @@ static cronet_engine *_engine = NULL;
 - (void)setUp {
   _service = self.class.host ? [RMTTestService serviceWithHost:self.class.host] : nil;
 #ifdef GRPC_COMPILE_WITH_CRONET
-  if (_engine == NULL) {
+  if (cronetEngine == NULL) {
+    // Cronet setup
     [Cronet setHttp2Enabled:YES];
-    [Cronet setSslKeyLogFileName:@"cronetkeylogfile.pem"];
     [Cronet start];
-    _engine = [Cronet getGlobalEngine];
-    [GRPCCall useCronet:_engine];
+    cronetEngine = [Cronet getGlobalEngine];
+    [GRPCCall useCronetWithEngine:cronetEngine];
   }
 #endif
 }