[DevTools] Separate ScreenCaptureModel out of ResourceTreeModel.

third_party/WebKit/Source/devtools/front_end/screencast/ScreencastApp.js

Index: third_party/WebKit/Source/devtools/front_end/screencast/ScreencastApp.js
diff --git a/third_party/WebKit/Source/devtools/front_end/screencast/ScreencastApp.js b/third_party/WebKit/Source/devtools/front_end/screencast/ScreencastApp.js
index 61c91c9c091379fbb08045f6fa1f5f9ca77ab33d..7e844f7555ab4a38eb686a8e51a45c006a032946 100644
--- a/third_party/WebKit/Source/devtools/front_end/screencast/ScreencastApp.js
+++ b/third_party/WebKit/Source/devtools/front_end/screencast/ScreencastApp.js
@@ -3,7 +3,7 @@
 // found in the LICENSE file.
 /**
  * @implements {Common.App}
- * @implements {SDK.TargetManager.Observer}
+ * @implements {SDK.SDKModelObserver<!SDK.ScreenCaptureModel>}
  * @unrestricted
  */
 Screencast.ScreencastApp = class {
@@ -11,8 +11,9 @@ Screencast.ScreencastApp = class {
     this._enabledSetting = Common.settings.createSetting('screencastEnabled', true);
     this._toggleButton = new UI.ToolbarToggle(Common.UIString('Toggle screencast'), 'largeicon-phone');
     this._toggleButton.setToggled(this._enabledSetting.get());
+    this._toggleButton.setEnabled(false);
     this._toggleButton.addEventListener(UI.ToolbarButton.Events.Click, this._toggleButtonClicked, this);
-    SDK.targetManager.observeTargets(this);
+    SDK.targetManager.observeModels(SDK.ScreenCaptureModel, this);
   }
 
   /**
@@ -44,38 +45,31 @@ Screencast.ScreencastApp = class {
 
   /**
    * @override
-   * @param {!SDK.Target} target
+   * @param {!SDK.ScreenCaptureModel} screenCaptureModel
    */
-  targetAdded(target) {
-    if (this._target)
+  modelAdded(screenCaptureModel) {
+    if (this._screenCaptureModel)
       return;
-    this._target = target;
-
-    var resourceTreeModel = SDK.ResourceTreeModel.fromTarget(target);
-    if (resourceTreeModel) {
-      this._screencastView = new Screencast.ScreencastView(target, resourceTreeModel);
-      this._rootSplitWidget.setMainWidget(this._screencastView);
-      this._screencastView.initialize();
-    } else {
-      this._toggleButton.setEnabled(false);
-    }
+    this._screenCaptureModel = screenCaptureModel;
+    this._toggleButton.setEnabled(true);
+    this._screencastView = new Screencast.ScreencastView(screenCaptureModel);
+    this._rootSplitWidget.setMainWidget(this._screencastView);
+    this._screencastView.initialize();
     this._onScreencastEnabledChanged();
   }
 
   /**
    * @override
-   * @param {!SDK.Target} target
+   * @param {!SDK.ScreenCaptureModel} screenCaptureModel
    */
-  targetRemoved(target) {
-    if (this._target === target) {
-      delete this._target;
-      if (!this._screencastView)
-        return;
-      this._toggleButton.setEnabled(false);
-      this._screencastView.detach();
-      delete this._screencastView;
-      this._onScreencastEnabledChanged();
-    }
+  modelRemoved(screenCaptureModel) {
+    if (this._screenCaptureModel !== screenCaptureModel)
+      return;
+    delete this._screenCaptureModel;
+    this._toggleButton.setEnabled(false);
+    this._screencastView.detach();
+    delete this._screencastView;
+    this._onScreencastEnabledChanged();
   }
 
   _toggleButtonClicked() {