Add sharedContainerID in configuration

FirebaseCore/Sources/FIROptions.m

@@ -29,6 +29,8 @@
 NSString *const kFIRStorageBucket = @"STORAGE_BUCKET";
 // The key to locate the expected bundle identifier in the plist file.
 NSString *const kFIRBundleID = @"BUNDLE_ID";
+// The key to locate the expected shared container identifier in the plist file.
+NSString *const kFIRSharedContainerID = @"SHARED_CONTAINER_ID";
 // The key to locate the project identifier in the plist file.
 NSString *const kFIRProjectID = @"PROJECT_ID";
 
@@ -332,6 +334,15 @@ - (void)setBundleID:(NSString *)bundleID {
   _optionsDictionary[kFIRBundleID] = [bundleID copy];
 }
 
+- (NSString *)sharedContainerID {
+  return self.optionsDictionary[kFIRSharedContainerID];
+}
+
+- (void)setSharedContainerID:(NSString *)sharedContainerID {
+  [self checkEditingLocked];
+  _optionsDictionary[kFIRSharedContainerID] = [sharedContainerID copy];
+}
+
 - (void)setAppGroupID:(NSString *)appGroupID {
   [self checkEditingLocked];
   _appGroupID = [appGroupID copy];

FirebaseCore/Sources/Public/FirebaseCore/FIROptions.h

@@ -42,6 +42,11 @@ NS_SWIFT_NAME(FirebaseOptions)
  */
 @property(nonatomic, copy) NSString *bundleID;
 
+/**
+ * The shared container ID for the application (useful for download/ upload from share extension). 
+ */
+@property(nonatomic, copy) NSString *sharedContainerID;
+
 /**
  * The OAuth2 client ID for iOS application used to authenticate Google users, for example
  * @"12345.apps.googleusercontent.com", used for signing in with Google.

FirebaseStorage/Sources/FIRStorage.m

@@ -86,6 +86,11 @@ + (GTMSessionFetcherService *)fetcherServiceForApp:(FIRApp *)app
       [fetcherService setRetryEnabled:YES];
       [fetcherService setRetryBlock:_retryWhenOffline];
       [fetcherService setAllowLocalhostRequest:YES];
+      [fetcherService setConfigurationBlock:^(GTMSessionFetcher * _Nonnull fetcher, NSURLSessionConfiguration * _Nonnull configuration) {
+        if (app.options.sharedContainerID != nil) {
+          configuration.sharedContainerIdentifier = app.options.sharedContainerID;
+        }
+      }];
       FIRStorageTokenAuthorizer *authorizer =
           [[FIRStorageTokenAuthorizer alloc] initWithGoogleAppID:app.options.googleAppID
                                                   fetcherService:fetcherService