V2 top bar no border (#1688)

* topBarNoBorder for ios

* Unit tests for topBarNoBorder

lib/ios/RNNNavigationOptions.h

 @property (nonatomic, strong) NSNumber* topBarTranslucent;
 @property (nonatomic, strong) NSString* tabBadge;
 @property (nonatomic, strong) NSNumber* topBarTextFontSize;
-
+@property (nonatomic, strong) NSNumber* topBarNoBorder;
 
 
 

lib/ios/RNNNavigationOptions.m

 	self.topBarTranslucent = [navigationOptions objectForKey:@"topBarTranslucent"];
 	self.tabBadge = [navigationOptions objectForKey:@"tabBadge"];
 	self.topBarTextFontSize = [navigationOptions objectForKey:@"topBarTextFontSize"];
-  
+	self.topBarNoBorder = [navigationOptions objectForKey:@"topBarNoBorder"];
+
 	return self;
 }
 
 		}		
 	}
 
+	if (self.topBarNoBorder) {
+		if ([self.topBarNoBorder boolValue]) {
+			viewController.navigationController.navigationBar
+			.shadowImage = [[UIImage alloc] init];
+		} else {
+			viewController.navigationController.navigationBar
+			.shadowImage = nil;
+		}
+	}
+
 }
 @end

lib/ios/ReactNativeNavigationTests/RNNRootViewControllerTest.m

 	//	XCTAssertThrows([self.uut viewWillAppear:false]);
 }
 
+-(void)testTopBarNoBorderOn {
+	NSNumber* topBarNoBorderInput = @(1);
+	self.options.topBarNoBorder = topBarNoBorderInput;
+	__unused UINavigationController* nav = [[UINavigationController alloc] initWithRootViewController:self.uut];
+	[self.uut viewWillAppear:false];
+	XCTAssertNotNil(self.uut.navigationController.navigationBar.shadowImage);
+}
+
+-(void)testTopBarNoBorderOff {
+	NSNumber* topBarNoBorderInput = @(0);
+	self.options.topBarNoBorder = topBarNoBorderInput;
+	__unused UINavigationController* nav = [[UINavigationController alloc] initWithRootViewController:self.uut];
+	[self.uut viewWillAppear:false];
+	XCTAssertNil(self.uut.navigationController.navigationBar.shadowImage);
+}
+
 @end