Bug 1435142 - Part 1: pref to enable close selected tab by dblclicking it. r=dao

MozReview-Commit-ID: ErulnUeVK0F

--HG--
extra : rebase_source : f9aaaa4ee6bf005e40b6f9f88255c589d2695e74

browser/app/profile/firefox.js

@@ -463,6 +463,7 @@ pref("browser.link.open_newwindow.disabled_in_fullscreen", false);
 #endif
 
 // Tabbed browser
+pref("browser.tabs.closeTabByDblclick", false);
 pref("browser.tabs.closeWindowWithLastTab", true);
 pref("browser.tabs.insertRelatedAfterCurrent", true);
 pref("browser.tabs.warnOnClose", true);

browser/base/content/tabbrowser.xml

@@ -143,6 +143,9 @@
 
           CustomizableUI.addListener(this);
           this._updateNewTabVisibility();
+
+          XPCOMUtils.defineLazyPreferenceGetter(this, "_closeTabByDblclick",
+            "browser.tabs.closeTabByDblclick", false);
         ]]>
       </constructor>
 
@@ -1689,6 +1692,7 @@
         ]]>
         </setter>
       </property>
+      <field name="_selectedOnFirstMouseDown">false</field>
 
       <property name="pinned" readonly="true">
         <getter>
@@ -1992,6 +1996,13 @@
 
       <handler event="mousedown" phase="capturing">
       <![CDATA[
+        let tabContainer = this.parentNode;
+        if (tabContainer._closeTabByDblclick &&
+            event.button == 0 &&
+            event.detail == 1) {
+          this._selectedOnFirstMouseDown = this.selected;
+        }
+
         if (this.selected) {
           this.style.MozUserFocus = "ignore";
         } else if (this.mOverCloseButton ||
@@ -2027,6 +2038,17 @@
         if (event.originalTarget.getAttribute("anonid") == "close-button") {
           event.stopPropagation();
         }
+
+        let tabContainer = this.parentNode;
+        if (tabContainer._closeTabByDblclick &&
+            this._selectedOnFirstMouseDown &&
+            this.selected &&
+            !this._overPlayingIcon) {
+          gBrowser.removeTab(this, {
+            animate: true,
+            byMouse: event.mozInputSource == MouseEvent.MOZ_SOURCE_MOUSE,
+          });
+        }
       ]]></handler>
 
       <handler event="animationend">