Moved |openedByDOM| to WebState's CreateParams and public interface.

ios/web/navigation/crw_session_controller.mm

Index: ios/web/navigation/crw_session_controller.mm
diff --git a/ios/web/navigation/crw_session_controller.mm b/ios/web/navigation/crw_session_controller.mm
index 91e7c1af2aa506e0a545b205d1cd98348810ca7f..008f3858a49e2ea13f1578187043736549279845 100644
--- a/ios/web/navigation/crw_session_controller.mm
+++ b/ios/web/navigation/crw_session_controller.mm
@@ -75,7 +75,6 @@ @interface CRWSessionController () {
 // Expose setters for serialization properties.  These are exposed in a category
 // in SessionStorageBuilder, and will be removed as ownership of
 // their backing ivars moves to NavigationManagerImpl.
-@property(nonatomic, readwrite, getter=isOpenedByDOM) BOOL openedByDOM;
 @property(nonatomic, readwrite, assign) NSInteger previousNavigationIndex;
 
 // Removes all items after currentNavigationIndex_.
@@ -99,14 +98,11 @@ @implementation CRWSessionController
 @synthesize currentNavigationIndex = _currentNavigationIndex;
 @synthesize previousNavigationIndex = _previousNavigationIndex;
 @synthesize pendingItemIndex = _pendingItemIndex;
-@synthesize openedByDOM = _openedByDOM;
 @synthesize sessionCertificatePolicyManager = _sessionCertificatePolicyManager;
 
-- (instancetype)initWithBrowserState:(web::BrowserState*)browserState
-                         openedByDOM:(BOOL)openedByDOM {
+- (instancetype)initWithBrowserState:(web::BrowserState*)browserState {
   self = [super init];
   if (self) {
-    _openedByDOM = openedByDOM;
     _browserState = browserState;
     _currentNavigationIndex = -1;
     _previousNavigationIndex = -1;