Bug 918329 - Fix XUL 'inline #text child' warning for the toolbarbutton element added in bug 762761, r=fitzgen

browser/devtools/debugger/debugger.xul

@@ -325,11 +325,10 @@
           </vbox>
           <toolbar id="sources-toolbar" class="devtools-toolbar">
             <toolbarbutton id="pretty-print"
+                           label="{}"
                            tooltiptext="&debuggerUI.sources.prettyPrint;"
                            class="devtools-toolbarbutton devtools-monospace"
-                           command="prettyPrintCommand">
-              {}
-            </toolbarbutton>
+                           command="prettyPrintCommand"/>
           </toolbar>
         </vbox>
         <splitter class="devtools-side-splitter"/>

browser/themes/linux/devtools/debugger.css

@@ -18,6 +18,7 @@
 }
 
 #pretty-print {
+  min-width: 0;
   font-weight: bold;
 }
 

browser/themes/osx/devtools/debugger.css

@@ -20,6 +20,7 @@
 }
 
 #pretty-print {
+  min-width: 0;
   font-weight: bold;
 }
 

browser/themes/windows/devtools/debugger.css

@@ -18,6 +18,7 @@
 }
 
 #pretty-print {
+  min-width: 0;
   font-weight: bold;
 }