[cronet] make startNetLogToFile write to correct file

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 215 matching lines @@
     [NSURLCache setSharedURLCache:gPreservedSharedURLCache];
     gPreservedSharedURLCache = nil;
   }
   [NSURLProtocol unregisterClass:[CRNPauseableHTTPProtocolHandler class]];
 }
 
 + (void)installIntoSessionConfiguration:(NSURLSessionConfiguration*)config {
   config.protocolClasses = @[ [CRNPauseableHTTPProtocolHandler class] ];
 }
 
-+ (void)startNetLogToFile:(NSString*)fileName logBytes:(BOOL)logBytes {
++ (bool)startNetLogToFile:(NSString*)fileName logBytes:(BOOL)logBytes {

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

BOOL

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

Done.

   if (gChromeNet.Get().get() && [fileName length]) {

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

I think it would be better if we did the validation first and return 'NO' if the
fileName is invalid. Thus, we would have less code inside the 'if' statement.

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

I wanted to keep the obj-c wrapper as thin as possible, and keep as much code as
possible in the cpp api.

(Right now though it does check filelength twice, and I think that should
change)

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

Acknowledged.

-    gChromeNet.Get()->StartNetLog([fileName UTF8String], logBytes);
+    NSURL* file =
+        [[[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory
+                                                 inDomains:NSUserDomainMask]
+            lastObject] URLByAppendingPathComponent:fileName];
+    return gChromeNet.Get()->StartNetLog(base::SysNSStringToUTF8([file path]), logBytes);
   }
+
+  return false;

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

Use 'NO' instead of 'false' since it is Objective C.

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

Done.

 }
 
 + (void)stopNetLog {
   if (gChromeNet.Get().get()) {
     gChromeNet.Get()->StopNetLog();
   }
 }
 
 + (NSString*)getUserAgent {
   if (!gChromeNet.Get().get()) {
@@ skipping 30 matching lines @@
   gHostResolverRulesForTesting = hostResolverRulesForTesting;
 }
 
 // This is a non-public dummy method that prevents the linker from stripping out
 // the otherwise non-referenced methods from 'cronet_bidirectional_stream.cc'.
 + (void)preventStrippingCronetBidirectionalStream {
   cronet_bidirectional_stream_create(NULL, 0, 0);
 }
 
 @end