Bug 1791067 - Allow inputs to shrink under their intrinsic size with flexbox emulation enabled. r=Gijs

Differential Revision: https://phabricator.services.mozilla.com/D157513

toolkit/themes/linux/global/search-textbox.css

@@ -28,6 +28,7 @@ html|input {
   text-shadow: inherit;
   box-sizing: border-box;
   -moz-box-flex: 1;
+  min-width: 0;
   text-align: inherit;
 }
 

toolkit/themes/osx/global/search-textbox.css

@@ -26,6 +26,7 @@ html|input {
   text-shadow: inherit;
   box-sizing: border-box;
   -moz-box-flex: 1;
+  min-width: 0;
   text-align: inherit;
 }
 

toolkit/themes/shared/global-shared.css

@@ -78,6 +78,11 @@
   padding: 0;
 }
 
+moz-input-box,
+html|input {
+  min-width: 0;
+}
+
 html|button,
 html|input,
 html|textarea {

toolkit/themes/windows/global/search-textbox.css

@@ -28,6 +28,7 @@ html|input {
   text-shadow: inherit;
   box-sizing: border-box;
   -moz-box-flex: 1;
+  min-width: 0;
   text-align: inherit;
 }