DevTools: do not discard soft context menu on glass pane mouseup unconditionally.

BUG=521457
TBR=dgozman
NOTRY=true

Review URL: https://codereview.chromium.org/1301603003

git-svn-id: svn://svn.chromium.org/blink/trunk@200745 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/devtools/front_end/ui/SoftContextMenu.js

@@ -329,6 +329,8 @@ WebInspector.SoftContextMenu.prototype = {
         // Return if this is simple 'click', since dispatched on glass pane, can't use 'click' event.
         if (new Date().getTime() - this._time < 300)
             return;
+        if (event.target === this.element)
+            return;
         this._discardMenu(true, event);
         event.consume();
     },