Introduce remove_reason enum in TabStripModelChange

In order to consider cases for ClosedTabCache feature separately,
turn bool 'will_be_deleted' into enum 'remove_reason', rename
TabStripModelChange::ContentsWithIndexAndWillBeDeleted to
TabStripModelChange::RemovedTab and use 'remove_reason' in it.

The following values have been introduced in enum RemoveReason:
- kDeleted to indicate that the WebContents will be deleted.
- kCached to indicate that WebContents will be stored in ClosedTabCache
  for some amount of time.
- kInsertedIntoOtherTabStrip to indicate that WebContents got detached
  from a TabStrip and inserted into another TabStrip.

Bug: 1149549
Change-Id: I715f61a8d1dbb4100d4a4cecdf91fba2ae0375c0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2782442
Reviewed-by: Sreeja Kamishetty <sreejakshetty@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Sreeja Kamishetty <sreejakshetty@chromium.org>
Cr-Commit-Position: refs/heads/master@{#891184}

AUTHORS

@@ -1088,6 +1088,7 @@ Timo Gurr <timo.gurr@gmail.com>
 Timo Reimann <ttr314@googlemail.com>
 Timo Witte <timo.witte@gmail.com>
 Ting Shao <ting.shao@intel.com>
+Tobias Soppa <tobias@soppa.me>
 Tom Callaway <tcallawa@redhat.com>
 Tom Harwood <tfh@skip.org>
 Tomas Popela <tomas.popela@gmail.com>

chrome/browser/extensions/api/tabs/tabs_event_router.cc

@@ -205,7 +205,8 @@ void TabsEventRouter::OnTabStripModelChanged(
     }
     case TabStripModelChange::kRemoved: {
       for (const auto& contents : change.GetRemove()->contents) {
-        if (contents.will_be_deleted) {
+        if (contents.remove_reason ==
+            TabStripModelChange::RemoveReason::kDeleted) {
           DispatchTabClosingAt(tab_strip_model, contents.contents,
                                contents.index);
         }

chrome/browser/metrics/desktop_session_duration/audible_contents_tracker.cc

@@ -38,7 +38,7 @@ void AudibleContentsTracker::OnTabStripModelChanged(
     const TabStripSelectionChange& selection) {
   if (change.type() == TabStripModelChange::kRemoved) {
     for (const auto& contents : change.GetRemove()->contents) {
-      if (contents.will_be_deleted)
+      if (contents.remove_reason == TabStripModelChange::RemoveReason::kDeleted)
         RemoveAudibleWebContents(contents.contents);
     }
   } else if (change.type() == TabStripModelChange::kReplaced) {

chrome/browser/supervised_user/supervised_user_url_filter_browsertest.cc

@@ -176,7 +176,9 @@ class TabClosingObserver : public TabStripModelObserver {
 
     auto* remove = change.GetRemove();
     for (const auto& contents : remove->contents) {
-      if (contents_ == contents.contents && contents.will_be_deleted) {
+      if (contents_ == contents.contents &&
+          contents.remove_reason ==
+              TabStripModelChange::RemoveReason::kDeleted) {
         if (run_loop_.running())
           run_loop_.Quit();
         contents_ = nullptr;

chrome/browser/ui/ash/shelf/browser_status_monitor.cc

@@ -234,7 +234,7 @@ void BrowserStatusMonitor::OnTabStripModelChanged(
   } else if (change.type() == TabStripModelChange::kRemoved) {
     auto* remove = change.GetRemove();
     for (const auto& contents : remove->contents) {
-      if (contents.will_be_deleted)
+      if (contents.remove_reason == TabStripModelChange::RemoveReason::kDeleted)
         OnTabClosing(contents.contents);
     }
   } else if (change.type() == TabStripModelChange::kReplaced) {

chrome/browser/ui/browser.cc

@@ -1150,7 +1150,8 @@ void Browser::OnTabStripModelChanged(TabStripModel* tab_strip_model,
     }
     case TabStripModelChange::kRemoved: {
       for (const auto& contents : change.GetRemove()->contents) {
-        if (contents.will_be_deleted)
+        if (contents.remove_reason ==
+            TabStripModelChange::RemoveReason::kDeleted)
           OnTabClosing(contents.contents);
         OnTabDetached(contents.contents,
                       contents.contents == selection.old_contents);

chrome/browser/ui/browser_browsertest.cc

@@ -207,7 +207,7 @@ class TabClosingObserver : public TabStripModelObserver {
 
     auto* remove = change.GetRemove();
     for (const auto& contents : remove->contents) {
-      if (contents.will_be_deleted)
+      if (contents.remove_reason == TabStripModelChange::RemoveReason::kDeleted)
         closing_count_ += 1;
     }
   }

chrome/browser/ui/tabs/tab_strip_model.cc

@@ -262,16 +262,16 @@ void TabStripModel::WebContentsData::WebContentsDestroyed() {
 }
 
 // Holds state for a WebContents that has been detached from the tab strip. Will
-// also handle WebContents deletion if |will_delete| is true.
+// also handle WebContents deletion if |remove_reason| is kDeleted.
 struct TabStripModel::DetachedWebContents {
   DetachedWebContents(int index_before_any_removals,
                       int index_at_time_of_removal,
                       std::unique_ptr<WebContents> contents,
-                      bool will_delete)
+                      TabStripModelChange::RemoveReason remove_reason)
       : contents(std::move(contents)),
         index_before_any_removals(index_before_any_removals),
         index_at_time_of_removal(index_at_time_of_removal),
-        will_delete(will_delete) {}
+        remove_reason(remove_reason) {}
   DetachedWebContents(const DetachedWebContents&) = delete;
   DetachedWebContents& operator=(const DetachedWebContents&) = delete;
   ~DetachedWebContents() = default;
@@ -289,8 +289,7 @@ struct TabStripModel::DetachedWebContents {
   // removed tabs in this batch.
   const int index_at_time_of_removal;
 
-  // Whether to delete the WebContents after sending notifications.
+  const TabStripModelChange::RemoveReason remove_reason;
-  const bool will_delete;
 };
 
 // Holds all state necessary to send notifications for detached tabs.
@@ -447,7 +446,9 @@ std::unique_ptr<content::WebContents> TabStripModel::DetachWebContentsAt(
       std::make_unique<DetachedWebContents>(
           index, index,
           DetachWebContentsImpl(index, /*create_historical_tab=*/false),
-          /*will_delete=*/false);
+          // TODO(https://crbug.com/2564529): Add case for kCached once the
+          // hooking logic is implemented.
+          TabStripModelChange::RemoveReason::kInsertedIntoOtherTabStrip);
   notifications.detached_web_contents.push_back(std::move(dwc));
   SendDetachWebContentsNotifications(&notifications);
   return std::move(notifications.detached_web_contents[0]->contents);
@@ -519,7 +520,7 @@ void TabStripModel::SendDetachWebContentsNotifications(
   for (auto& dwc : notifications->detached_web_contents) {
     remove.contents.push_back({dwc->contents.get(),
                                dwc->index_before_any_removals,
-                               dwc->will_delete});
+                               dwc->remove_reason});
   }
   TabStripModelChange change(std::move(remove));
 
@@ -544,7 +545,7 @@ void TabStripModel::SendDetachWebContentsNotifications(
   }
 
   for (auto& dwc : notifications->detached_web_contents) {
-    if (dwc->will_delete) {
+    if (dwc->remove_reason == TabStripModelChange::RemoveReason::kDeleted) {
       // This destroys the WebContents, which will also send
       // WebContentsDestroyed notifications.
       dwc->contents.reset();
@@ -1877,7 +1878,7 @@ bool TabStripModel::CloseWebContentses(
             original_indices[i], current_index,
             DetachWebContentsImpl(current_index,
                                   close_types & CLOSE_CREATE_HISTORICAL_TAB),
-            /*will_delete=*/true);
+            TabStripModelChange::RemoveReason::kDeleted);
     notifications->detached_web_contents.push_back(std::move(dwc));
   }
 

chrome/browser/ui/tabs/tab_strip_model_observer.cc

@@ -72,12 +72,12 @@ TabStripModelChange::TabStripModelChange(Type type,
                                          std::unique_ptr<Delta> delta)
     : type_(type), delta_(std::move(delta)) {}
 
-void TabStripModelChange::ContentsWithIndexAndWillBeDeleted::WriteIntoTrace(
+void TabStripModelChange::RemovedTab::WriteIntoTrace(
     perfetto::TracedValue context) const {
   auto dict = std::move(context).WriteDictionary();
   dict.Add("contents", contents);
   dict.Add("index", index);
-  dict.Add("will_be_deleted", will_be_deleted);
+  dict.Add("remove_reason", remove_reason);
 }
 
 void TabStripModelChange::ContentsWithIndex::WriteIntoTrace(

chrome/browser/ui/tabs/tab_strip_model_observer.h

@@ -38,6 +38,21 @@ class TabStripModelChange {
  public:
   enum Type { kSelectionOnly, kInserted, kRemoved, kMoved, kReplaced };
 
+  // Used to specify what will happen with the WebContents after it is removed.
+  enum class RemoveReason {
+    // WebContents will be deleted.
+    kDeleted,
+
+    // WebContents will be stored in ClosedTabCache. After some amount of time,
+    // the WebContents will either be deleted, or inserted back into another
+    // TabStripModel.
+    kCached,
+
+    // WebContents got detached from a TabStrip and inserted into another
+    // TabStrip.
+    kInsertedIntoOtherTabStrip
+  };
+
   // Base class for all changes.
   // TODO(dfried): would love to change this whole thing into a std::variant,
   // but C++17 features are not yet approved for use in chromium.
@@ -47,16 +62,12 @@ class TabStripModelChange {
     virtual void WriteIntoTrace(perfetto::TracedValue context) const = 0;
   };
 
-  struct ContentsWithIndexAndWillBeDeleted {
+  struct RemovedTab {
+    void WriteIntoTrace(perfetto::TracedValue context) const;
+
     content::WebContents* contents;
     int index;
-
+    RemoveReason remove_reason;
-    // The specified WebContents are being closed (and eventually destroyed).
-    // TODO(https://crbug.com/1149549): Make will_be_deleted into enum to
-    // consider the case for ClosedTabCache feature separtely.
-    bool will_be_deleted;
-
-    void WriteIntoTrace(perfetto::TracedValue context) const;
   };
 
   struct ContentsWithIndex {
@@ -110,7 +121,7 @@ class TabStripModelChange {
     Remove& operator=(Remove&& other);
 
     // Contains the list of web contents removed with their indexes at
-    // the time of removal along with flag |will_be_deleted| that indicates if
+    // the time of removal along with flag |remove_reason| that indicates if
     // the web contents will be deleted or not after removing. For example, if
     // we removed elements:
     //
@@ -133,7 +144,7 @@ class TabStripModelChange {
     // them in the order the web contents appear in |contents|. Observers should
     // not do index-based queries based on their own internally-stored indices
     // until after processing all of |contents|.
-    std::vector<ContentsWithIndexAndWillBeDeleted> contents;
+    std::vector<RemovedTab> contents;
 
     void WriteIntoTrace(perfetto::TracedValue context) const override;
   };

chrome/browser/ui/tabs/tab_strip_model_stats_recorder.cc

@@ -146,7 +146,7 @@ void TabStripModelStatsRecorder::OnTabStripModelChanged(
     const TabStripSelectionChange& selection) {
   if (change.type() == TabStripModelChange::kRemoved) {
     for (const auto& contents : change.GetRemove()->contents) {
-      if (contents.will_be_deleted)
+      if (contents.remove_reason == TabStripModelChange::RemoveReason::kDeleted)
         OnTabClosing(contents.contents);
     }
   } else if (change.type() == TabStripModelChange::kReplaced) {

chrome/browser/ui/tabs/tab_strip_model_unittest.cc

@@ -251,7 +251,8 @@ class MockTabStripModelObserver : public TabStripModelObserver {
       }
       case TabStripModelChange::kRemoved: {
         for (const auto& contents : change.GetRemove()->contents) {
-          if (contents.will_be_deleted)
+          if (contents.remove_reason ==
+              TabStripModelChange::RemoveReason::kDeleted)
             PushCloseState(contents.contents, contents.index);
           PushDetachState(contents.contents, contents.index,
                           selection.old_contents == contents.contents);

chrome/browser/ui/user_education/active_tab_tracker.cc

@@ -50,7 +50,8 @@ void ActiveTabTracker::OnTabStripModelChanged(
     // Ignore if the tab isn't being closed (this would happen if it were
     // dragged to a different tab strip).
       for (const auto& contents : remove->contents) {
-        if (contents.will_be_deleted &&
+        if (contents.remove_reason ==
+                TabStripModelChange::RemoveReason::kDeleted &&
             contents.index == prev_active_tab_index) {
           active_tab_closed_callback_.Run(
               model, clock_->NowTicks() - active_tab_changed_times_[model]);

chrome/browser/ui/web_applications/web_app_metrics.cc

@@ -203,9 +203,10 @@ void WebAppMetrics::OnTabStripModelChanged(
   }
 
   if (change.type() == TabStripModelChange::kRemoved) {
-    for (const TabStripModelChange::ContentsWithIndexAndWillBeDeleted&
+    for (const TabStripModelChange::RemovedTab& contents :
-             contents : change.GetRemove()->contents) {
+         change.GetRemove()->contents) {
-      if (contents.will_be_deleted) {
+      if (contents.remove_reason ==
+          TabStripModelChange::RemoveReason::kDeleted) {
         auto* tab_helper =
             WebAppTabHelperBase::FromWebContents(contents.contents);
         if (tab_helper && !tab_helper->GetAppId().empty())