Bug 773563 - Cleanup BTA_detach callers to avoid redundant state checks; r=robcee

toolkit/devtools/server/actors/webbrowser.js

@@ -606,8 +606,7 @@ BrowserTabActor.prototype = {
       return;
     }
 
-    if (this.attached) {
-      this._detach();
+    if (this._detach()) {
       this.conn.send({ from: this.actorID,
                        type: "tabDetached" });
     }
@@ -675,10 +674,12 @@ BrowserTabActor.prototype = {
 
   /**
    * Does the actual work of detaching from a tab.
+   *
+   * @returns false if the tab wasn't attached or true of detahing succeeds.
    */
   _detach: function BTA_detach() {
     if (!this.attached) {
-      return;
+      return false;
     }
 
     if (this._progressListener) {
@@ -699,6 +700,7 @@ BrowserTabActor.prototype = {
     }
 
     this._attached = false;
+    return true;
   },
 
   // Protocol Request Handlers
@@ -714,12 +716,10 @@ BrowserTabActor.prototype = {
   },
 
   onDetach: function BTA_onDetach(aRequest) {
-    if (!this.attached) {
+    if (!this._detach()) {
       return { error: "wrongState" };
     }
 
-    this._detach();
-
     return { type: "detached" };
   },