Fixing an edge case in CRWBrowsingDataStore

ios/web/public/crw_browsing_data_store.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef IOS_WEB_CRW_BROWSING_DATA_STORE_H_
 #define IOS_WEB_CRW_BROWSING_DATA_STORE_H_
 
 #import <Foundation/Foundation.h>
 
 #import "base/ios/block_types.h"
@@ skipping 29 matching lines @@
 // (UIWebView and WKWebView) uses.
 // All methods must be called on the UI thread.
 @interface CRWBrowsingDataStore : NSObject
 
 // Designated initializer. |browserState| cannot be a nullptr.
 // The |web::ActiveStateManager| associated with |browserState| needs to be in
 // active state.
 - (instancetype)initWithBrowserState:(web::BrowserState*)browserState
     NS_DESIGNATED_INITIALIZER;
 
-// The mode that the CRWBrowsingDataStore is in.
+// The mode that the CRWBrowsingDataStore is in. KVO compliant.
 @property(nonatomic, assign, readonly) CRWBrowsingDataStoreMode mode;
 
 // TODO(shreyasv): Verify the preconditions for the following 3 methods when
 // web::WebViewCounter class is implemented. crbug.com/480507
 
 // Changes the mode to |ACTIVE|.
-// |completionHandler| is called on the main thread.
+// |completionHandler| is called on the main thread. This block has no return
+// value and takes a single BOOL argument that indicates whether or not the
+// the mode was successfully changed to |ACTIVE|.
+// The mode change to |ACTIVE| can fail if another |makeActive| or
+// |makeInactive| was enqueued after this call.
 // Precondition: There must be no web views associated with the BrowserState.
-// Note: If there is another operation driven to change the mode, the mode will
-// still be |SYNCHRONIZING| rather than |ACTIVE| when the callback is received.
-- (void)makeActiveWithCompletionHandler:(ProceduralBlock)completionHandler;
+- (void)makeActiveWithCompletionHandler:
+        (void (^)(BOOL success))completionHandler;
 
 // Changes the mode to |INACTIVE|.
-// |completionHandler| is called on the main thread.
+// |completionHandler| is called on the main thread. This block has no return
+// value and takes a single BOOL argument that indicates whether or not the
+// the mode was successfully changed to |INACTIVE|.
+// The mode change to |ACTIVE| can fail if another |makeActive| or
+// |makeInactive| was enqueued after this call.
 // Precondition: There must be no web views associated with the BrowserState.
-// Note: If there is another operation driven to change the mode, the mode will
-// still be |SYNCHRONIZING| rather than |INACTIVE| when the callback is
-// received.
-- (void)makeInactiveWithCompletionHandler:(ProceduralBlock)completionHandler;
+- (void)makeInactiveWithCompletionHandler:
+        (void (^)(BOOL success))completionHandler;
 
 // Removes all browsing data of the provided |browsingDataTypes|.
 // |completionHandler| is called on the main thread after the browsing data has
 // been removed.
 // Precondition: There must be no web views associated with the BrowserState.
 - (void)removeDataOfTypes:(web::BrowsingDataTypes)browsingDataTypes
         completionHandler:(ProceduralBlock)completionHandler;
 
 // Returns YES if there is still a pending operation that has not finished
 // running. Creating web views (UIWebViews and WKWebViews) with this
 // CRWBrowsingDataStore when there are pending operations is undefined
 // behavior.
 @property(nonatomic, assign, readonly) BOOL hasPendingOperations;
 
 @end
 
 #endif  // IOS_WEB_CRW_BROWSING_DATA_STORE_H_