[cronet] make startNetLogToFile write to correct file

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..72316d74070fa2120fd23816040cd210cc105bb4 100644
--- a/components/cronet/ios/Cronet.h
+++ b/components/cronet/ios/Cronet.h
@@ -78,7 +78,7 @@ CRONET_EXPORT
 // by |logBytes| - if YES then LOG_ALL otherwise LOG_ALL_BUT_BYTES. If the file
 // exists it is truncated before starting. If actively logging the call is
 // ignored.
-+ (void)startNetLogToFile:(NSString*)fileName logBytes:(BOOL)logBytes;
++ (bool)startNetLogToFile:(NSString*)fileName logBytes:(BOOL)logBytes;

[mef, 2016/11/10 17:09:48]

nit: ObjC uses capital BOOL.

[kapishnikov, 2016/11/10 20:52:17]

If the method can fail, should we add NSError** as an out argument to the
method? See
https://developer.apple.com/library/prerelease/content/documentation/Cocoa/Co...

[lilyhoughton, 2016/11/16 16:04:09]

it can only fail in one way (unable to open file), so having an out-argument
seemed excessive, but I can add an optional one.

[lilyhoughton, 2016/11/16 16:04:10]

Done.

[kapishnikov, 2016/11/18 22:17:27]

It can actually fail for multiple reasons, e.g. the user passed NULL, an invalid
value, the directory doesn't exist, there is no permission to write to the file,
i.e. everywhere the method return NO/false. Since it is a debug API, I am okay
to keep the method signature as is but I think there could be some benefit to
return an error message that describes what went wrong.

 
 // Stop net-internals logging and flush file to disk. If a logging session is
 // not in progress this call is ignored.