Use silk icons

The silk icons [1] look a little more modern than the tango icons and
the set contains a bigger variation of icons.

The silk icons are available under the Creative Commons Attribution
3.0 License.

For some icons (arrowDown.png, arrowUp.png, arrowRight.png,
draftComments.png and queryIcon.png) the origin is unclear and hence
we should no longer use them.

The origin of deleteNormal.png and deleteHover.png is also unclear but
at the moment we don't have a good replacement for them.

The magnifying glass icon that was used as query icon is replaced by a
spy glasses icon. This is because the magnifying glass is associated
with zoom and not with find/query.

Some icons from the tango icon library [2] (goNext.png, goPrev.png,
goUp.png, listAdd.png) are still used because there is no suitable
replacement for them in the silk icons set.

Some unused icons have been removed.

In the source code the icons are now grouped by origin. This should
make it more obvious when icons of unknown origin are added.

[1] http://famfamfam.com/lab/icons/silk/
[2] http://tango.freedesktop.org/Tango_Icon_Library

Change-Id: I5e153647c60410115d06da1a706a0ec1ecdfcaed
Signed-off-by: Edwin Kempin <ekempin@google.com>

gerrit-gwtui/src/main/java/com/google/gerrit/client/GerritCss.java

@@ -160,6 +160,7 @@ public interface GerritCss extends CssResource {
   String projectFilterLabel();
   String projectFilterPanel();
   String projectNameColumn();
+  String queryIcon();
   String rebaseContentPanel();
   String rebaseSuggestBox();
   String registerScreenExplain();

gerrit-gwtui/src/main/java/com/google/gerrit/client/admin/AdminResources.java

@@ -24,12 +24,19 @@ public interface AdminResources extends ClientBundle {
   @Source("admin.css")
   AdminCss css();
 
+  /**
+   * unknown origin
+   * TODO replace icons
+   */
   @Source("deleteNormal.png")
   ImageResource deleteNormal();
 
   @Source("deleteHover.png")
   ImageResource deleteHover();
 
-  @Source("undoNormal.png")
+  /**
+   * silk icons (CC-BY3.0): http://famfamfam.com/lab/icons/silk/
+   */
+  @Source("arrow_undo.png")
   ImageResource undoNormal();
 }

gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/Resources.java

@@ -25,6 +25,10 @@ interface Resources extends ClientBundle {
   @Source("CommentBox.css") CommentBox.Style style();
   @Source("Scrollbar.css") Scrollbar.Style scrollbarStyle();
 
+  /**
+   * tango icon library (public domain):
+   * http://tango.freedesktop.org/Tango_Icon_Library
+   */
   @Source("goPrev.png") ImageResource goPrev();
   @Source("goNext.png") ImageResource goNext();
   @Source("goUp.png") ImageResource goUp();

gerrit-gwtui/src/main/java/com/google/gerrit/client/gerrit.css

@@ -1306,6 +1306,12 @@ a:hover.downloadLink {
   min-width: 300px;
 }
 
+.queryIcon {
+  position: relative;
+  top: 2px;
+  margin-right: 3px;
+}
+
 /** ProjectSettings */
 .maxObjectSizeLimitEffectiveLabel {
   padding-top: 5px;

gerrit-gwtui/src/main/java/com/google/gerrit/client/ui/ProjectSearchLink.java

@@ -27,6 +27,7 @@ public class ProjectSearchLink extends InlineHyperlink {
     super(" ", PageLinks.toProjectDefaultDashboard(projectName));
     setTitle(Util.C.projectListQueryLink());
     final Image image = new Image(Gerrit.RESOURCES.queryIcon());
+    image.setStyleName(Gerrit.RESOURCES.css().queryIcon());
     DOM.insertBefore(getElement(), image.getElement(),
         DOM.getFirstChild(getElement()));
   }