Store TabGroupData values directly in group_map_

A unique_ptr<> was used inside a std::map, but std::map values are
already stable in memory. We can directly store TabGroupData values
without indirection and still hand out TabGroupData pointers.

Bug: 905491
Change-Id: I250b156e56dc400a83374e57e06958fa5f06864f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1719446
Commit-Queue: Bret Sepulveda <bsep@chromium.org>
Reviewed-by: Bret Sepulveda <bsep@chromium.org>
Cr-Commit-Position: refs/heads/master@{#681069}

chrome/browser/ui/tabs/tab_group_data.h

@@ -15,6 +15,8 @@ class TabGroupData {
  public:
   // Construct a TabGroupData with placeholder name and random color.
   TabGroupData();
+  TabGroupData(const TabGroupData& other) = default;
+  TabGroupData(TabGroupData&& other) = default;
   ~TabGroupData() = default;
 
   base::string16 title() const { return title_; }
@@ -30,8 +32,6 @@ class TabGroupData {
   base::string16 title_;
   SkColor color_;
   int tab_count_;
-
-  DISALLOW_COPY_AND_ASSIGN(TabGroupData);
 };
 
 #endif  // CHROME_BROWSER_UI_TABS_TAB_GROUP_DATA_H_

chrome/browser/ui/tabs/tab_strip_model.cc

@@ -780,7 +780,7 @@ bool TabStripModel::IsTabBlocked(int index) const {
 
 const TabGroupData* TabStripModel::GetDataForGroup(TabGroupId group) const {
   DCHECK(base::Contains(group_data_, group));
-  return group_data_.at(group).get();
+  return &group_data_.at(group);
 }
 
 base::Optional<TabGroupId> TabStripModel::GetTabGroupForTab(int index) const {
@@ -1488,7 +1488,7 @@ int TabStripModel::InsertWebContentsAtImpl(
   }
   data->set_group(group);
   if (group.has_value())
-    group_data_[group.value()]->TabAdded();
+    group_data_[group.value()].TabAdded();
 
   // TODO(gbillock): Ask the modal dialog manager whether the WebContents should
   // be blocked, or just let the modal dialog manager make the blocking call
@@ -1759,7 +1759,7 @@ void TabStripModel::AddToNewGroupImpl(const std::vector<int>& indices,
       contents_data_.cbegin(), contents_data_.cend(),
       [new_group](const auto& datum) { return datum->group() == new_group; }));
 
-  group_data_[new_group] = std::make_unique<TabGroupData>();
+  group_data_.emplace(new_group, TabGroupData());
 
   // Find a destination for the first tab that's not inside another group. We
   // will stack the rest of the tabs up to its right.
@@ -1843,7 +1843,7 @@ void TabStripModel::MoveAndSetGroup(int index,
     MoveWebContentsAtImpl(index, new_index, false);
   contents_data_[new_index]->set_group(new_group);
   if (new_group.has_value())
-    group_data_[new_group.value()]->TabAdded();
+    group_data_[new_group.value()].TabAdded();
 
   NotifyGroupChange(new_index, old_group, new_group);
 }
@@ -1870,7 +1870,7 @@ base::Optional<TabGroupId> TabStripModel::UngroupTab(int index) {
     return base::nullopt;
 
   contents_data_[index]->set_group(base::nullopt);
-  TabGroupData* group_data = group_data_[group.value()].get();
+  TabGroupData* group_data = &group_data_[group.value()];
   group_data->TabRemoved();
   // Delete the group if we just ungrouped the last tab in that group.
   if (group_data->empty())

chrome/browser/ui/tabs/tab_strip_model.h

@@ -34,7 +34,6 @@
 #endif
 
 class Profile;
-class TabGroupData;
 class TabStripModelDelegate;
 
 namespace content {
@@ -325,7 +324,8 @@ class TabStripModel {
   // https://crbug.com/915956).
   base::Optional<TabGroupId> GetTabGroupForTab(int index) const;
 
-  // Returns the TabGroupData instance for the given |group|.
+  // Returns the TabGroupData instance for the given |group|. The returned
+  // pointer is valid until all tabs in |group| are destroyed.
   const TabGroupData* GetDataForGroup(TabGroupId group) const;
 
   // Returns a list of tab groups that contain at least one tab in this strip.
@@ -668,7 +668,7 @@ class TabStripModel {
 
   // The data for tab groups hosted within this TabStripModel, indexed by the
   // group ID.
-  std::map<TabGroupId, std::unique_ptr<TabGroupData>> group_data_;
+  std::map<TabGroupId, TabGroupData> group_data_;
 
   TabStripModelDelegate* delegate_;