[ios] TabIdTabHelper

ios/chrome/browser/tabs/tab.mm

Index: ios/chrome/browser/tabs/tab.mm
diff --git a/ios/chrome/browser/tabs/tab.mm b/ios/chrome/browser/tabs/tab.mm
index 90ddf437ecb4d217afc81fff327f9c681f5491d4..e03bf262949a69fcb56cb315bb8c9fba977a5fd4 100644
--- a/ios/chrome/browser/tabs/tab.mm
+++ b/ios/chrome/browser/tabs/tab.mm
@@ -100,6 +100,7 @@
 #import "ios/chrome/browser/web/navigation_manager_util.h"
 #import "ios/chrome/browser/web/passkit_dialog_provider.h"
 #include "ios/chrome/browser/web/print_observer.h"
+#import "ios/chrome/browser/web/tab_id_tab_helper.h"
 #import "ios/chrome/browser/xcallback_parameters.h"
 #include "ios/chrome/grit/ios_strings.h"
 #import "ios/web/navigation/navigation_item_impl.h"
@@ -155,10 +156,6 @@ class TabHistoryContext;
 class FaviconDriverObserverBridge;
 class TabInfoBarObserver;
 
-// The key under which the Tab ID is stored in the WebState's serializable user
-// data.
-NSString* const kTabIDKey = @"TabID";
-
 // Name of histogram for recording the state of the tab when the renderer is
 // terminated.
 const char kRendererTerminationStateHistogram[] =
@@ -426,7 +423,7 @@ void TabInfoBarObserver::OnInfoBarReplaced(infobars::InfoBar* old_infobar,
 @implementation Tab
 
 @synthesize browserState = _browserState;
-@synthesize tabId = tabId_;
+@dynamic tabId;

[marq (ping after 24h), 2017/06/23 08:46:29]

You only need @dynamic when no implementation of the property is provided in
this implementation; @dynamic is an assurance to the complier that some other
code will handle accessing the property.

For this change, just deleting the @synthesize line is sufficient.

[edchin, 2017/06/23 16:24:21]

Done.

 @synthesize useGreyImageCache = useGreyImageCache_;
 @synthesize isPrerenderTab = _isPrerenderTab;
 @synthesize isLinkLoadingPrerenderTab = isLinkLoadingPrerenderTab_;
@@ -615,22 +612,8 @@ void TabInfoBarObserver::OnInfoBarReplaced(infobars::InfoBar* old_infobar,
     // tabId should be nil.
     return nil;
   }
-
-  if (tabId_)
-    return tabId_;
-
-  web::SerializableUserDataManager* userDataManager =
-      web::SerializableUserDataManager::FromWebState(self.webState);
-  NSString* tabId = base::mac::ObjCCast<NSString>(
-      userDataManager->GetValueForSerializationKey(kTabIDKey));
-
-  if (!tabId || ![tabId length]) {
-    tabId = [[NSUUID UUID] UUIDString];
-    userDataManager->AddSerializableData(tabId, kTabIDKey);
-  }
-
-  tabId_ = [tabId copy];
-  return tabId_;
+  return base::SysUTF8ToNSString(
+      TabIDTabHelper::FromWebState(self.webState)->tab_id());

[rohitrao (ping after 24h), 2017/06/23 11:10:27]

Is the TabID always used as an NSString?  If so, should we just store that in
the helper instead of a std::string?

[edchin, 2017/06/23 16:24:21]

My original intent is to be consistent with ios/web (which prefers std::string
over NSString)
since this class derives from an ios/web class. However, looking at other recent
subclasses of web::WebStateUserData, it is precedented to use NSString.
I have updated this to use NSString.

 }
 
 - (web::WebState*)webState {