DevTools -> Memory Tab -> Allowing to edit a title of a heap snapshot

third_party/WebKit/Source/devtools/front_end/profiler/HeapSnapshotView.js

Index: third_party/WebKit/Source/devtools/front_end/profiler/HeapSnapshotView.js
diff --git a/third_party/WebKit/Source/devtools/front_end/profiler/HeapSnapshotView.js b/third_party/WebKit/Source/devtools/front_end/profiler/HeapSnapshotView.js
index 04707a96a1fca6a2e5cf762c9aca6a7cdc027a35..16120b8d8337b30d1f09d61665d80d91632ea414 100644
--- a/third_party/WebKit/Source/devtools/front_end/profiler/HeapSnapshotView.js
+++ b/third_party/WebKit/Source/devtools/front_end/profiler/HeapSnapshotView.js
@@ -251,6 +251,7 @@ Profiler.HeapSnapshotView = class extends UI.SimpleView {
     if (this._profile.profileType() !== Profiler.ProfileTypeRegistry.instance.trackingHeapSnapshotProfileType)
       result.push(this._baseSelect, this._filterSelect);
     result.push(this._selectedSizeText);
+    this._updateControls();

[alph, 2017/07/11 18:44:23]

Oh, got it. Thanks!

So the title updates for older profiles do not come to the HeapSnapshotView's
created later, as they do not subscribe to these (because the newer views do not
get _onReceiveSnapshot called for already existing snapshots). This is a bit
awkward that a view have listeners for title change for newer profiles, but not
for older ones. I see two options to make it consistent:

1.
Keep this _updateControls call, but remove the listener for title change on the
view for foreign profiles. E.g add a check: if (profile == this._profile)
profile.addEventlistener(...);
to the _onReceiveSnapshot

2.
Remove this _updateControls call, and add something like:

for (var existingProfile of this._profiles()) {
  existingProfile.addEventListener(
      Profiler.ProfileHeader.Events.ProfileTitleChanged, this._updateControls,
this);
}

to the HeapSnapshotView constructor. To make sure the view subscribes to title
change for all the profiles.

[diana.suvorova, 2017/07/11 19:19:53]

I see. This makes sense.  I went with option #2.

     return result;
   }
 
@@ -607,33 +608,33 @@ Profiler.HeapSnapshotView = class extends UI.SimpleView {
 
   _updateBaseOptions() {
     var list = this._profiles();
-    // We're assuming that snapshots can only be added.
-    if (this._baseSelect.size() === list.length)
-      return;
+    var selectedIndex = this._baseSelect.selectedIndex();
 
-    for (var i = this._baseSelect.size(), n = list.length; i < n; ++i) {
-      var title = list[i].title;
-      this._baseSelect.createOption(title);
-    }
+    this._baseSelect.removeOptions();
+    for (var item of list)
+      this._baseSelect.createOption(item.title);
+
+    if (selectedIndex > -1)
+      this._baseSelect.setSelectedIndex(selectedIndex);
   }
 
   _updateFilterOptions() {
     var list = this._profiles();
-    // We're assuming that snapshots can only be added.
-    if (this._filterSelect.size() - 1 === list.length)
-      return;
+    var selectedIndex = this._filterSelect.selectedIndex();
 
-    if (!this._filterSelect.size())
-      this._filterSelect.createOption(Common.UIString('All objects'));
-
-    for (var i = this._filterSelect.size() - 1, n = list.length; i < n; ++i) {
-      var title = list[i].title;
+    this._filterSelect.removeOptions();
+    this._filterSelect.createOption(Common.UIString('All objects'));
+    for (var i = 0; i < list.length; ++i) {
+      var title;
       if (!i)
-        title = Common.UIString('Objects allocated before %s', title);
+        title = Common.UIString('Objects allocated before %s', list[i].title);
       else
-        title = Common.UIString('Objects allocated between %s and %s', list[i - 1].title, title);
+        title = Common.UIString('Objects allocated between %s and %s', list[i - 1].title, list[i].title);
       this._filterSelect.createOption(title);
     }
+
+    if (selectedIndex > -1)
+      this._filterSelect.setSelectedIndex(selectedIndex);
   }
 
   _updateControls() {
@@ -647,6 +648,8 @@ Profiler.HeapSnapshotView = class extends UI.SimpleView {
    */
   _onReceiveSnapshot(event) {
     this._updateControls();
+    var profile = event.data;
+    profile.addEventListener(Profiler.ProfileHeader.Events.ProfileTitleChanged, this._updateControls, this);
   }
 
   /**
@@ -654,6 +657,8 @@ Profiler.HeapSnapshotView = class extends UI.SimpleView {
    */
   _onProfileHeaderRemoved(event) {
     var profile = event.data;
+    profile.removeEventListener(Profiler.ProfileHeader.Events.ProfileTitleChanged, this._updateControls, this);
+
     if (this._profile === profile) {
       this.detach();
       this._profile.profileType().removeEventListener(