Moving gRPC support interfaces out of cronet and into a new component.

components/cronet/ios/Cronet.h

Index: components/cronet/ios/Cronet.h
diff --git a/components/cronet/ios/Cronet.h b/components/cronet/ios/Cronet.h
index d87f4a6848881c0311a9fc252ebfe086babea851..7e20415ee2e836fdf7d27d60c4d593f9a9b64481 100644
--- a/components/cronet/ios/Cronet.h
+++ b/components/cronet/ios/Cronet.h
@@ -4,14 +4,16 @@
 
 #import <Foundation/Foundation.h>
 
-#include "cronet_c_for_grpc.h"
+#include "bidirectional_stream_c.h"
 
 // A block, that takes a request, and returns YES if the request should
 // be handled.
 typedef BOOL (^RequestFilterBlock)(NSURLRequest* request);
 
 // Interface for installing Cronet.
-CRONET_EXPORT
+// TODO(gcasto): Should this macro be separate from the one defined in
+// bidirectional_stream_c.h?
+GRPC_SUPPORT_EXPORT
 @interface Cronet : NSObject
 
 // Sets whether HTTP/2 should be supported by CronetEngine. This method only has
@@ -89,7 +91,7 @@ CRONET_EXPORT
 + (NSString*)getUserAgent;
 
 // Get a pointer to global instance of cronet_engine for GRPC C API.
-+ (cronet_engine*)getGlobalEngine;
++ (stream_engine*)getGlobalEngine;
 
 // Returns differences in metrics collected by Cronet since the last call to
 // getGlobalMetricsDeltas, serialized as a [protobuf]