[net-internals] Fix JS exception on stopping capturing while in Capture view

chrome/browser/resources/net_internals/tab_switcher_view.js

Index: chrome/browser/resources/net_internals/tab_switcher_view.js
diff --git a/chrome/browser/resources/net_internals/tab_switcher_view.js b/chrome/browser/resources/net_internals/tab_switcher_view.js
index fadc3d7af0462396afdc50ee0ed0723a987387a7..8badcf0fda46db095947b5e6fd031ef4c4e64b10 100644
--- a/chrome/browser/resources/net_internals/tab_switcher_view.js
+++ b/chrome/browser/resources/net_internals/tab_switcher_view.js
@@ -31,8 +31,8 @@ var TabSwitcherView = (function() {
 
     this.tabIdToView_ = {};
     this.tabIdToLink_ = {};
-    // Ordered list of views.
-    this.viewList_ = [];
+    // Map from tab id to the views link visiblity.
+    this.tabIdsLinkVisibility_ = new Map();
     this.activeTabId_ = null;
 
     this.onTabSwitched_ = opt_onTabSwitched;
@@ -98,7 +98,7 @@ var TabSwitcherView = (function() {
       }
 
       this.tabIdToView_[tabId] = view;
-      this.viewList_.push(view);
+      this.tabIdsLinkVisibility_.set(tabId, true);
 
       var node = addNodeWithText($(TAB_LIST_ID), 'a', name);
       node.href = hash;
@@ -115,13 +115,16 @@ var TabSwitcherView = (function() {
       var wasActive = this.activeTabId_ == tabId;
 
       setNodeDisplay(this.tabIdToLink_[tabId], isVisible);
+      this.tabIdsLinkVisibility_.set(tabId, isVisible);
 
       if (wasActive && !isVisible) {
         // If the link for active tab is being hidden, then switch to the first
         // tab which is still visible.
-        for (var view in this.viewList_) {

[eroman, 2016/07/06 20:06:29]

I agree that the current code is quite wrong.

The problem with your proposed map from tabId --> visibility is the visibility
state is never updated in the map (whereas before it queried the underlying
View). At a minimum this is a layering issue.

Instead I think we can accomplish this using the existing tabIdToView map:

for (var curTabId in this.tabIdToView_) {
  var curView = thistabIdToView_[curTabId];
   if (curView.isVisible())
     this.switchToTab(curTabId);
     break;
}

-          if (view.isVisible())
-            this.switchToTab(option.value);
+        for (var [localTabId, enabled] of this.tabIdsLinkVisibility_) {
+          if (enabled) {
+            this.switchToTab(localTabId);
+            break;
+          }
         }
       }
     },