Makes DatagramClientSocket::GetBoundNetwork const.

(Breaking out connection migration CL https://codereview.chromium.org/1327923002/.)

R=rch@chromium.org,pauljensen@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1541003003

Cr-Commit-Position: refs/heads/master@{#367008}

net/dns/address_sorter_posix_unittest.cc

@@ -66,7 +66,7 @@ class TestUDPClientSocket : public DatagramClientSocket {
     NOTIMPLEMENTED();
     return ERR_NOT_IMPLEMENTED;
   }
-  NetworkChangeNotifier::NetworkHandle GetBoundNetwork() override {
+  NetworkChangeNotifier::NetworkHandle GetBoundNetwork() const override {
     return NetworkChangeNotifier::kInvalidNetworkHandle;
   }
 

net/socket/socket_test_util.cc

@@ -1350,7 +1350,8 @@ int MockUDPClientSocket::BindToDefaultNetwork() {
   return ERR_NOT_IMPLEMENTED;
 }
 
-NetworkChangeNotifier::NetworkHandle MockUDPClientSocket::GetBoundNetwork() {
+NetworkChangeNotifier::NetworkHandle MockUDPClientSocket::GetBoundNetwork()
+    const {
   return NetworkChangeNotifier::kInvalidNetworkHandle;
 }
 

net/socket/socket_test_util.h

@@ -736,7 +736,7 @@ class MockUDPClientSocket : public DatagramClientSocket, public AsyncSocket {
   // DatagramClientSocket implementation.
   int BindToNetwork(NetworkChangeNotifier::NetworkHandle network) override;
   int BindToDefaultNetwork() override;
-  NetworkChangeNotifier::NetworkHandle GetBoundNetwork() override;
+  NetworkChangeNotifier::NetworkHandle GetBoundNetwork() const override;
   int Connect(const IPEndPoint& address) override;
 
   // AsyncSocket implementation.

net/udp/datagram_client_socket.h

@@ -32,7 +32,7 @@ class NET_EXPORT_PRIVATE DatagramClientSocket : public DatagramSocket,
   // Returns the network that either BindToNetwork() or BindToDefaultNetwork()
   // bound this socket to. Returns NetworkChangeNotifier::kInvalidNetworkHandle
   // if not explicitly bound via BindToNetwork() or BindToDefaultNetwork().
-  virtual NetworkChangeNotifier::NetworkHandle GetBoundNetwork() = 0;
+  virtual NetworkChangeNotifier::NetworkHandle GetBoundNetwork() const = 0;
 
   // Initialize this socket as a client socket to server at |address|.
   // Returns a network error code.

net/udp/udp_client_socket.cc

@@ -53,7 +53,7 @@ int UDPClientSocket::BindToDefaultNetwork() {
   return rv;
 }
 
-NetworkChangeNotifier::NetworkHandle UDPClientSocket::GetBoundNetwork() {
+NetworkChangeNotifier::NetworkHandle UDPClientSocket::GetBoundNetwork() const {
   return network_;
 }
 

net/udp/udp_client_socket.h

@@ -29,7 +29,7 @@ class NET_EXPORT_PRIVATE UDPClientSocket : public DatagramClientSocket {
   // DatagramClientSocket implementation.
   int BindToNetwork(NetworkChangeNotifier::NetworkHandle network) override;
   int BindToDefaultNetwork() override;
-  NetworkChangeNotifier::NetworkHandle GetBoundNetwork() override;
+  NetworkChangeNotifier::NetworkHandle GetBoundNetwork() const override;
   int Connect(const IPEndPoint& address) override;
   int Read(IOBuffer* buf,
            int buf_len,