[DevTools] Make resource tree model optional

third_party/WebKit/Source/devtools/front_end/sdk/TargetManager.js

Index: third_party/WebKit/Source/devtools/front_end/sdk/TargetManager.js
diff --git a/third_party/WebKit/Source/devtools/front_end/sdk/TargetManager.js b/third_party/WebKit/Source/devtools/front_end/sdk/TargetManager.js
index 02623fe55fef3466c10686d2cee117103124892f..29b762b6e8479d9a5379d33e5a922117538cdc52 100644
--- a/third_party/WebKit/Source/devtools/front_end/sdk/TargetManager.js
+++ b/third_party/WebKit/Source/devtools/front_end/sdk/TargetManager.js
@@ -31,6 +31,8 @@ WebInspector.TargetManager.Events = {
     SuspendStateChanged: "SuspendStateChanged"
 }
 
+WebInspector.TargetManager._ListenersSymbol = Symbol("WebInspector.TargetManager.Listeners");

[dgozman, 2016/08/19 20:23:37]

style: _listenersSymbol

[eostroukhov, 2016/08/20 01:22:31]

Done.

+
 WebInspector.TargetManager.prototype = {
     suspendAllTargets: function()
     {
@@ -99,8 +101,14 @@ WebInspector.TargetManager.prototype = {
      */
     reloadPage: function(bypassCache, injectedScript)
     {
-        if (this._targets.length)
-            this._targets[0].resourceTreeModel.reloadPage(bypassCache, injectedScript);
+        if (!this._targets.length)
+            return;
+
+        var resourceTreeModel = WebInspector.ResourceTreeModel.fromTarget(this._targets[0]);
+        if (!resourceTreeModel)
+            return;
+
+        resourceTreeModel.reloadPage(bypassCache, injectedScript);
     },
 
     /**
@@ -186,20 +194,20 @@ WebInspector.TargetManager.prototype = {
         target.runtimeModel = new WebInspector.RuntimeModel(target);
 
         var networkManager = null;
-        if (target.hasNetworkCapability())
+        var resourceTreeModel = null;
+        if (target.hasNetworkCapability()) {
             networkManager = new WebInspector.NetworkManager(target);
-
-        var securityOriginManager = WebInspector.SecurityOriginManager.fromTarget(target);
-        /** @type {!WebInspector.ResourceTreeModel} */
-        target.resourceTreeModel = new WebInspector.ResourceTreeModel(target, networkManager, securityOriginManager);
-
-        if (networkManager)
-            new WebInspector.NetworkLog(target, target.resourceTreeModel, networkManager);
+            if (target.hasDOMCapability()) {
+                var securityOriginManager = WebInspector.SecurityOriginManager.fromTarget(target);

[dgozman, 2016/08/19 20:23:37]

Inline this one?

[eostroukhov, 2016/08/20 01:22:31]

Done.

+                resourceTreeModel = new WebInspector.ResourceTreeModel(target, networkManager, securityOriginManager);
+                new WebInspector.NetworkLog(target, resourceTreeModel, networkManager);

[dgozman, 2016/08/19 20:23:37]

nit: let's avoid nested if's here. Instead I propose to list all dependencies in
each if statement, e.g.:

if (resourceTreeModel && networkManager)
    new WebInspector.NetworkLog(target, resourceTreeModel, networkManager);

[eostroukhov, 2016/08/20 01:22:31]

Done.

+            }
+        }
 
         if (target.hasJSCapability())
             new WebInspector.DebuggerModel(target);
 
-        if (target.hasDOMCapability()) {
+        if (resourceTreeModel) {

[dgozman, 2016/08/19 20:23:37]

Why this change? If DOMModel or CSSModel cannot work without ResourceTreeModel,
why don't we pass it in constructor?

[eostroukhov, 2016/08/20 01:22:31]

I was trying to do this in an earlier CL - ultimately we decided against it as
it looks like the CSSModel should not depend on RTM but this can't be fixed
right now.

[dgozman, 2016/08/20 01:32:00]

Let's add a TODO here then.

[eostroukhov-old, 2016/08/22 17:55:41]

Done.

             var domModel = new WebInspector.DOMModel(target);
             new WebInspector.CSSModel(target, domModel);
         }
@@ -236,10 +244,15 @@ WebInspector.TargetManager.prototype = {
     {
         this._targets.push(target);
         if (this._targets.length === 1) {
-            target.resourceTreeModel.addEventListener(WebInspector.ResourceTreeModel.EventTypes.MainFrameNavigated, this._redispatchEvent, this);
-            target.resourceTreeModel.addEventListener(WebInspector.ResourceTreeModel.EventTypes.Load, this._redispatchEvent, this);
-            target.resourceTreeModel.addEventListener(WebInspector.ResourceTreeModel.EventTypes.PageReloadRequested, this._redispatchEvent, this);
-            target.resourceTreeModel.addEventListener(WebInspector.ResourceTreeModel.EventTypes.WillReloadPage, this._redispatchEvent, this);
+            var resourceTreeModel = WebInspector.ResourceTreeModel.fromTarget(target);
+            if (resourceTreeModel) {
+                var listeners = [];
+                listeners.push(resourceTreeModel.addEventListener(WebInspector.ResourceTreeModel.EventTypes.MainFrameNavigated, this._redispatchEvent, this));

[dgozman, 2016/08/19 20:23:37]

nit: instead of push, we can inline:
resourceTreeModel[symbol] = [
    ...,
    ...,
];

[eostroukhov, 2016/08/20 01:22:31]

Done.

+                listeners.push(resourceTreeModel.addEventListener(WebInspector.ResourceTreeModel.EventTypes.Load, this._redispatchEvent, this));
+                listeners.push(resourceTreeModel.addEventListener(WebInspector.ResourceTreeModel.EventTypes.PageReloadRequested, this._redispatchEvent, this));
+                listeners.push(resourceTreeModel.addEventListener(WebInspector.ResourceTreeModel.EventTypes.WillReloadPage, this._redispatchEvent, this));
+                resourceTreeModel[WebInspector.TargetManager._ListenersSymbol] = listeners;
+            }
         }
         var copy = this._observersForTarget(target);
         for (var i = 0; i < copy.length; ++i)
@@ -261,11 +274,11 @@ WebInspector.TargetManager.prototype = {
     removeTarget: function(target)
     {
         this._targets.remove(target);
-        if (this._targets.length === 0) {
-            target.resourceTreeModel.removeEventListener(WebInspector.ResourceTreeModel.EventTypes.MainFrameNavigated, this._redispatchEvent, this);
-            target.resourceTreeModel.removeEventListener(WebInspector.ResourceTreeModel.EventTypes.Load, this._redispatchEvent, this);
-            target.resourceTreeModel.removeEventListener(WebInspector.ResourceTreeModel.EventTypes.WillReloadPage, this._redispatchEvent, this);
-        }
+        var resourceTreeModel = WebInspector.ResourceTreeModel.fromTarget(target);
+        var treeModelListeners = resourceTreeModel && resourceTreeModel[WebInspector.TargetManager._ListenersSymbol];
+        if (treeModelListeners)
+            WebInspector.EventTarget.removeEventListeners(treeModelListeners);
+
         var copy = this._observersForTarget(target);
         for (var i = 0; i < copy.length; ++i)
             copy[i].targetRemoved(target);