Move resources from gerrit-gwtui to gerrit-gwtui-common

This allows plugins to use the standard Gerrit icons.

There is now a single place were icons are stored (in
com.google.gerrit.client in gerrit-gwtui-common). Before they were
distributed over different packages. An exception are a few icons in
com.google.gerrit.client.admin and com.google.gerrit.client.diff which
cannot be moved since they are referenced from a css file in the same
package (at least I don't know how to link to the icons in
gerrit-gwtui-common from the css files).

The icon names were made consistent, duplicate icons were deleted and
the icons are also moved from src/main/java/ to src/main/resources/.

In addition the only gif icon was converted to png.

Change-Id: Ibd9475ae175de6acc7c36bf2e40f96b003f2af10

gerrit-gwtui-common/BUCK

@@ -1,9 +1,11 @@
 SRC = 'src/main/java/com/google/gerrit/'
+DIFFY = glob(['src/main/resources/com/google/gerrit/client/diffy*.png'])
 
 gwt_module(
   name = 'client',
   srcs = glob([SRC + 'client/**/*.java']),
   gwt_xml = SRC + 'GerritGwtUICommon.gwt.xml',
+  resources = glob(['src/main/**/*']),
   deps = ['//lib/gwt:user'],
   visibility = ['PUBLIC'],
 )
@@ -28,3 +30,25 @@ java_library(
   resources = glob(['src/main/**/*']),
   visibility = ['PUBLIC'],
 )
+
+prebuilt_jar(
+  name = 'diffy_logo',
+  binary_jar = ':diffy_image_files_ln',
+  deps = [
+    '//lib:LICENSE-diffy',
+    '//lib:LICENSE-CC-BY3.0',
+  ],
+  visibility = ['PUBLIC'],
+)
+
+genrule(
+  name = 'diffy_image_files_ln',
+  cmd = 'ln -s $(location :diffy_image_files) $OUT',
+  deps = [':diffy_image_files'],
+  out = 'diffy_images.jar',
+)
+
+java_library(
+  name = 'diffy_image_files',
+  resources = DIFFY,
+)