Remove obsolete PauseableHttpProtocolHandler class.

ios/net/crn_http_protocol_handler.mm

Index: ios/net/crn_http_protocol_handler.mm
diff --git a/ios/net/crn_http_protocol_handler.mm b/ios/net/crn_http_protocol_handler.mm
index bb9ac3b279565d8253a5c71e5f389356d34f57f7..d2855b4e2aebe73594100d0c81cdb470557ab22d 100644
--- a/ios/net/crn_http_protocol_handler.mm
+++ b/ios/net/crn_http_protocol_handler.mm
@@ -1030,77 +1030,3 @@ void HttpProtocolHandlerCore::PushClients(NSArray* clients) {
 }
 
 @end
-
-#pragma mark -
-#pragma mark PauseableHttpProtocolHandler
-
-// The HttpProtocolHandler is called by the iOS system to handle the
-// NSURLRequest. This HttpProtocolHandler conforms to the observed semantics of
-// NSURLProtocol when used with NSURLSession on iOS 8 - i.e., |-startLoading|
-// means "start or resume request" and |-stopLoading| means "pause request".
-// Since there is no way to actually pause a request in the network stack, this
-// is implemented using a subclass of CRNHTTPProtocolHandlerProxy that knows how
-// to defer callbacks.
-//
-// Note that this class conforms to somewhat complex threading rules:
-// 1) |initWithRequest:cachedResponse:client:| and |dealloc| can be called on
-//    any thread.
-// 2) |startLoading| and |stopLoading| are always called on the client thread.
-// 3) |stopLoading| is called before |dealloc| is called.
-//
-// The main wrinkle is that |dealloc|, which may be called on any thread, needs
-// to clean up a running network request. To do this, |dealloc| needs to run
-// |cancelRequest|, which needs to be run on the client thread. Since it is
-// guaranteed that |startLoading| is called before |dealloc| is called, the
-// |startLoading| method stores a pointer to the client thread, then |dealloc|
-// asks that client thread to perform the |cancelRequest| selector via
-// |scheduleCancelRequest|.
-//
-// Some of the above logic is implemented in the parent class
-// (CRNHTTPProtocolHandler) because it is convenient.
-@implementation CRNPauseableHTTPProtocolHandler {
-  BOOL _started;
-  dispatch_queue_t _queue;
-}
-
-#pragma mark NSURLProtocol methods
-
-- (void)dealloc {
-  [self scheduleCancelRequest];
-}
-
-#pragma mark NSURLProtocol overrides.
-
-- (void)startLoading {
-  if (_started) {
-    [[self getProtocolHandlerProxy] resume];
-    return;
-  }
-
-  _started = YES;
-  [super startLoading];
-}
-
-- (void)stopLoading {
-  [[self getProtocolHandlerProxy] pause];
-}
-
-// This method has unusual concurrency properties. It can be called on any
-// thread, but it must be called from |-dealloc|, which guarantees that no other
-// method of this object is running concurrently (since |-dealloc| is only
-// called when the last reference to the object drops).
-//
-// This method takes a reference to _core to ensure that _core lives long enough
-// to have the request cleanly cancelled.
-- (void)scheduleCancelRequest {
-  DeferredCancellation* cancellation =
-      [[DeferredCancellation alloc] initWithCore:[self getCore]];
-  NSArray* modes = @[ [[NSRunLoop currentRunLoop] currentMode] ];
-  [cancellation performSelector:@selector(cancel)
-                       onThread:[self getClientThread]
-                     withObject:nil
-                  waitUntilDone:NO
-                          modes:modes];
-}
-
-@end