Reinstate "iOS - Add iceRegatherIntervalRange."

This reverts commit 93adc3209b5ff10adaba54d5eab6b53bc2780685.

Reverted originally because it depended on a CL which was reverted.
That CL has been reinstated in:

https: //chromium-review.googlesource.com/#/c/572070/
Bug: webrtc:7969
Change-Id: I608bbeaaba02e84908433c8260cf236df0307a97
Reviewed-on: https://chromium-review.googlesource.com/572405
Reviewed-by: Zeke Chin <tkchin@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#19035}
diff --git a/webrtc/sdk/objc/Framework/UnitTests/RTCConfigurationTest.mm b/webrtc/sdk/objc/Framework/UnitTests/RTCConfigurationTest.mm
index df94d4f..4b44fb1 100644
--- a/webrtc/sdk/objc/Framework/UnitTests/RTCConfigurationTest.mm
+++ b/webrtc/sdk/objc/Framework/UnitTests/RTCConfigurationTest.mm
@@ -18,6 +18,7 @@
 #import "RTCConfiguration+Private.h"
 #import "WebRTC/RTCConfiguration.h"
 #import "WebRTC/RTCIceServer.h"
+#import "WebRTC/RTCIntervalRange.h"
 
 @interface RTCConfigurationTest : NSObject
 - (void)testConversionToNativeConfiguration;
@@ -29,6 +30,7 @@
 - (void)testConversionToNativeConfiguration {
   NSArray *urlStrings = @[ @"stun:stun1.example.net" ];
   RTCIceServer *server = [[RTCIceServer alloc] initWithURLStrings:urlStrings];
+  RTCIntervalRange *range = [[RTCIntervalRange alloc] initWithMin:0 max:100];
 
   RTCConfiguration *config = [[RTCConfiguration alloc] init];
   config.iceServers = @[ server ];
@@ -47,6 +49,7 @@
   config.continualGatheringPolicy =
       RTCContinualGatheringPolicyGatherContinually;
   config.shouldPruneTurnPorts = YES;
+  config.iceRegatherIntervalRange = range;
 
   std::unique_ptr<webrtc::PeerConnectionInterface::RTCConfiguration>
       nativeConfig([config createNativeConfiguration]);
@@ -73,11 +76,14 @@
   EXPECT_EQ(webrtc::PeerConnectionInterface::GATHER_CONTINUALLY,
             nativeConfig->continual_gathering_policy);
   EXPECT_EQ(true, nativeConfig->prune_turn_ports);
+  EXPECT_EQ(range.min, nativeConfig->ice_regather_interval_range->min());
+  EXPECT_EQ(range.max, nativeConfig->ice_regather_interval_range->max());
 }
 
 - (void)testNativeConversionToConfiguration {
   NSArray *urlStrings = @[ @"stun:stun1.example.net" ];
   RTCIceServer *server = [[RTCIceServer alloc] initWithURLStrings:urlStrings];
+  RTCIntervalRange *range = [[RTCIntervalRange alloc] initWithMin:0 max:100];
 
   RTCConfiguration *config = [[RTCConfiguration alloc] init];
   config.iceServers = @[ server ];
@@ -96,6 +102,7 @@
   config.continualGatheringPolicy =
       RTCContinualGatheringPolicyGatherContinually;
   config.shouldPruneTurnPorts = YES;
+  config.iceRegatherIntervalRange = range;
 
   webrtc::PeerConnectionInterface::RTCConfiguration *nativeConfig =
       [config createNativeConfiguration];
@@ -121,6 +128,8 @@
             newConfig.iceBackupCandidatePairPingInterval);
   EXPECT_EQ(config.continualGatheringPolicy, newConfig.continualGatheringPolicy);
   EXPECT_EQ(config.shouldPruneTurnPorts, newConfig.shouldPruneTurnPorts);
+  EXPECT_EQ(config.iceRegatherIntervalRange.min, newConfig.iceRegatherIntervalRange.min);
+  EXPECT_EQ(config.iceRegatherIntervalRange.max, newConfig.iceRegatherIntervalRange.max);
 }
 
 @end