Gallery.app: make edit button toggleable.

ui/file_manager/gallery/css/gallery.css

Index: ui/file_manager/gallery/css/gallery.css
diff --git a/ui/file_manager/gallery/css/gallery.css b/ui/file_manager/gallery/css/gallery.css
index 397b4714d8d1fb5540be26a6fa69d40d2ed79eb0..076c80bbd11c1246f33d5fbf7a971bd5a7d2544f 100644
--- a/ui/file_manager/gallery/css/gallery.css
+++ b/ui/file_manager/gallery/css/gallery.css
@@ -574,7 +574,8 @@ files-toggle-ripple::shadow .ripple.activated {
   visibility: visible;
 }
 
-.gallery > .toolbar paper-button {
+.gallery > .toolbar paper-button,
+.gallery > .toolbar button {
   background-position: center;
   background-repeat: no-repeat;
   height: 32px;
@@ -583,11 +584,33 @@ files-toggle-ripple::shadow .ripple.activated {
   width: 32px;
 }
 
+.gallery > .toolbar button {
+  background-color: transparent;
+  border: 0;
+  padding: 0;
+  position: relative;
+}
+
+.gallery > .toolbar button > .icon {
+  background-position: center;
+  background-repeat: no-repeat;
+  height: 100%;
+  position: relative;
+  width: 100%;
+  z-index: 2;
+}
+
+.gallery > .toolbar button > files-toggle-ripple {
+  position: absolute;
+  top: 0;
+  z-index: 1;
+}
+
 .gallery > .toolbar paper-button:focus {
   background-color: rgba(0, 0, 0, 0.3);
 }
 
-.gallery > .toolbar paper-button.edit {
+.gallery > .toolbar button.edit > .icon {
   background-image: -webkit-image-set(
       url(../images/100/edit.png) 1x,
       url(../images/200/edit.png) 2x);
@@ -634,10 +657,11 @@ files-toggle-ripple::shadow .ripple.activated {
   pointer-events: none;
 }
 
-.gallery:not([editing])[mode='slide'] > .toolbar .button.slide-mode,
-.gallery:not([editing])[mode='thumbnail'] > .toolbar .button.thumbnail-mode,
-.gallery[editing][mode='slide'] > .toolbar .button.thumbnail-mode,
-.gallery > .toolbar paper-button[disabled] {
+.gallery:not([editing])[mode='slide'] > paper-button.slide-mode,
+.gallery:not([editing])[mode='thumbnail'] > paper-button.thumbnail-mode,
+.gallery[editing][mode='slide'] > paper-button.thumbnail-mode,
+paper-button[disabled],
+button[disabled] {
   display: none;
 }