Add warning for deprecated API to indicate that the passed in domain name's scheme will deduced as https

Firebase/DynamicLinks/CHANGELOG.md

@@ -1,4 +1,5 @@
-# v3.1.2
+# v3.2.0
+- Add support for creating and receiving dynamic links from custom domains. This feature is not yet available for public consumption. (#1962, #2017, #2078)
 - Delete deprecated source files. (#2038)
 
 # v3.1.1

Firebase/DynamicLinks/FDLURLComponents/FDLURLComponents.m

@@ -452,13 +452,21 @@ @implementation FIRDynamicLinkComponents
 #pragma mark Deprecated Initializers.
 + (instancetype)componentsWithLink:(NSURL *)link domain:(NSString *)domain {
   NSURL *domainURL = [NSURL URLWithString:domain];
+  if (!domainURL.scheme) {
+    FDLLog(FDLLogLevelWarning, FDLLogIdentifierSetupWarnHTTPSScheme,
+           @"Only https scheme is allowed. The supplied domain's scheme will be treated as https.");
+  }
   NSString *domainURIPrefix =
       domainURL.scheme ? domain : [NSString stringWithFormat:@"https://%@", domain];
   return [FIRDynamicLinkComponents componentsWithLink:link domainURIPrefix:domainURIPrefix];
 }
 
 - (instancetype)initWithLink:(NSURL *)link domain:(NSString *)domain {
   NSURL *domainURL = [NSURL URLWithString:domain];
+  if (!domainURL.scheme) {
+    FDLLog(FDLLogLevelWarning, FDLLogIdentifierSetupWarnHTTPSScheme,
+           @"Only https scheme is allowed. The supplied domain's scheme will be treated as https.");
+  }
   NSString *domainURIPrefix =
       domainURL.scheme ? domain : [NSString stringWithFormat:@"https://%@", domain];
   return [self initWithLink:link domainURIPrefix:domainURIPrefix];
@@ -472,7 +480,7 @@ + (instancetype)componentsWithLink:(NSURL *)link domainURIPrefix:(NSString *)dom
            @"Invalid domainURIPrefix. Please input a valid URL.");
     return nil;
   }
-  if (![[domainURIPrefixURL.scheme lowercaseString] hasPrefix:@"https"]) {
+  if (![[domainURIPrefixURL.scheme lowercaseString] isEqualToString:@"https"]) {
     FDLLog(FDLLogLevelError, FDLLogIdentifierSetupInvalidDomainURIPrefixScheme,
            @"Invalid domainURIPrefix scheme. Scheme needs to be https");
     return nil;
@@ -491,7 +499,7 @@ - (instancetype)initWithLink:(NSURL *)link domainURIPrefix:(NSString *)domainURI
              @"Invalid domainURIPrefix. Please input a valid URL.");
       return nil;
     }
-    if (![[domainURIPrefixURL.scheme lowercaseString] hasPrefix:@"https"]) {
+    if (![[domainURIPrefixURL.scheme lowercaseString] isEqualToString:@"https"]) {
       FDLLog(FDLLogLevelError, FDLLogIdentifierSetupInvalidDomainURIPrefixScheme,
              @"Invalid domainURIPrefix scheme. Scheme needs to be https");
       return nil;

Firebase/DynamicLinks/Logging/FDLLogging.h

@@ -35,6 +35,7 @@ typedef NS_ENUM(NSInteger, FDLLogIdentifier) {
   FDLLogIdentifierSetupNonDefaultApp = 2,
   FDLLogIdentifierSetupInvalidDomainURIPrefixScheme = 3,
   FDLLogIdentifierSetupInvalidDomainURIPrefix = 4,
+  FDLLogIdentifierSetupWarnHTTPSScheme = 5,
 };
 
 /** The appropriate formatter for using NSInteger in FIRLogger. */

Firebase/DynamicLinks/Public/FDLURLComponents.h

@@ -512,7 +512,8 @@ FIR_SWIFT_NAME(DynamicLinkComponents)
  * @param link Deep link to be stored in created Dynamic link. This link also called "payload" of
  *     the Dynamic link.
  * @param domain Domain of your App. This value must be equal to your assigned domain from Firebase
- *     Console.
+ *     Console. (e.g. xyz.page.link). Note that the domain scheme is required to be https and is
+ * assumed as such by this API.
  */
 + (instancetype)componentsWithLink:(NSURL *)link
                             domain:(NSString *)domain
@@ -527,7 +528,8 @@ FIR_SWIFT_NAME(DynamicLinkComponents)
  * @param link Deep link to be stored in created Dynamic link. This link also called "payload" of
  *     the Dynamic link.
  * @param domain Domain of your App. This value must be equal to your assigned domain from Firebase
- *     Console.
+ *     Console. (e.g. xyz.page.link). Note that the domain scheme is required to be https and is
+ * assumed as such by this API.
  */
 - (instancetype)initWithLink:(NSURL *)link
                       domain:(NSString *)domain