[DevTools] Turn starting tracing into promise.

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 1a9538188b849f665b823e03d16b52f3a9be61fa..a886fb934aca06325d894bcfb084aa675a45ae4a 100644
--- a/third_party/WebKit/Source/devtools/front_end/sdk/TargetManager.js
+++ b/third_party/WebKit/Source/devtools/front_end/sdk/TargetManager.js
@@ -379,24 +379,6 @@ SDK.TargetManager = class extends Common.Object {
   }
 
   /**
-   * @param {!SDK.Target} target
-   */
-  suspendReload(target) {
-    var resourceTreeModel = SDK.ResourceTreeModel.fromTarget(target);
-    if (resourceTreeModel)
-      resourceTreeModel.suspendReload();
-  }
-
-  /**
-   * @param {!SDK.Target} target
-   */
-  resumeReload(target) {
-    var resourceTreeModel = SDK.ResourceTreeModel.fromTarget(target);
-    if (resourceTreeModel)
-      setImmediate(resourceTreeModel.resumeReload.bind(resourceTreeModel));
-  }
-
-  /**
    * @param {function()} webSocketConnectionLostCallback
    */
   connectToMainTarget(webSocketConnectionLostCallback) {