diff --git a/java/com/google/gitiles/doc/ImageLoader.java b/java/com/google/gitiles/doc/ImageLoader.java
index b7b2531..3e536d7 100644
--- a/java/com/google/gitiles/doc/ImageLoader.java
+++ b/java/com/google/gitiles/doc/ImageLoader.java
@@ -18,7 +18,6 @@
 import com.google.common.io.BaseEncoding;
 import com.google.gitiles.GitilesView;
 import com.google.gitiles.MimeTypes;
-import com.google.template.soy.shared.restricted.EscapingConventions.FilterImageDataUri;
 import java.io.IOException;
 import javax.annotation.Nullable;
 import org.eclipse.jgit.errors.LargeObjectException;
@@ -54,7 +53,8 @@
     if (data != null) {
       return data;
     }
-    return FilterImageDataUri.INSTANCE.getInnocuousOutput();
+    // Otherwise return something that is both clearly an image, but clearly invalid.
+    return SoyConstants.IMAGE_URI_INNOCUOUS_OUTPUT;
   }
 
   private String inlineMaybe(@Nullable String markdownPath, String imagePath) {
diff --git a/java/com/google/gitiles/doc/MarkdownToHtml.java b/java/com/google/gitiles/doc/MarkdownToHtml.java
index f6289e2..64758b2 100644
--- a/java/com/google/gitiles/doc/MarkdownToHtml.java
+++ b/java/com/google/gitiles/doc/MarkdownToHtml.java
@@ -24,8 +24,6 @@
 import com.google.gitiles.doc.html.HtmlBuilder;
 import com.google.gitiles.doc.html.SoyHtmlBuilder;
 import com.google.template.soy.data.SanitizedContent;
-import com.google.template.soy.shared.restricted.EscapingConventions.FilterImageDataUri;
-import com.google.template.soy.shared.restricted.EscapingConventions.FilterNormalizeUri;
 import java.util.List;
 import javax.annotation.Nullable;
 import org.commonmark.ext.gfm.strikethrough.Strikethrough;
@@ -402,7 +400,7 @@
       if (HtmlBuilder.isValidGitUri(target)) {
         return target;
       }
-      return FilterNormalizeUri.INSTANCE.getInnocuousOutput();
+      return SoyConstants.NORMAL_URI_INNOCUOUS_OUTPUT;
     }
 
     String anchor = "";
@@ -414,7 +412,7 @@
 
     String dest = PathResolver.resolve(filePath, target);
     if (dest == null || view == null) {
-      return FilterNormalizeUri.INSTANCE.getInnocuousOutput();
+      return SoyConstants.NORMAL_URI_INNOCUOUS_OUTPUT;
     }
 
     GitilesView.Builder b;
@@ -442,7 +440,7 @@
     } else if (imageLoader != null) {
       return imageLoader.inline(filePath, dest);
     }
-    return FilterImageDataUri.INSTANCE.getInnocuousOutput();
+    return SoyConstants.IMAGE_URI_INNOCUOUS_OUTPUT;
   }
 
   public void visit(TableBlock node) {
diff --git a/java/com/google/gitiles/doc/Navbar.java b/java/com/google/gitiles/doc/Navbar.java
index cd63e3f..d936d9f 100644
--- a/java/com/google/gitiles/doc/Navbar.java
+++ b/java/com/google/gitiles/doc/Navbar.java
@@ -19,7 +19,6 @@
 import com.google.common.base.CharMatcher;
 import com.google.common.base.Splitter;
 import com.google.gitiles.doc.html.HtmlBuilder;
-import com.google.template.soy.shared.restricted.EscapingConventions.FilterImageDataUri;
 import com.google.template.soy.shared.restricted.Sanitizers;
 import java.util.HashMap;
 import java.util.Map;
@@ -85,7 +84,7 @@
     } else if (HtmlBuilder.isImageDataUri(url)) {
       return Sanitizers.filterImageDataUri(url);
     } else {
-      return FilterImageDataUri.INSTANCE.getInnocuousOutput();
+      return SoyConstants.IMAGE_URI_INNOCUOUS_OUTPUT;
     }
   }
 
diff --git a/java/com/google/gitiles/doc/SoyConstants.java b/java/com/google/gitiles/doc/SoyConstants.java
new file mode 100644
index 0000000..d56382c
--- /dev/null
+++ b/java/com/google/gitiles/doc/SoyConstants.java
@@ -0,0 +1,50 @@
+// Copyright 2018 Google Inc. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gitiles.doc;
+
+/**
+ * Constant definitions for Soy utilities.
+ *
+ * <p>These constant definitions are copied from Soy internal packages, and are repeated here at the
+ * request of Soy team to limit our dependencies on their internal packages. The text still refers
+ * to "zSoyz" for consistency with other non-Markdown parts of Gitiles.
+ */
+final class SoyConstants {
+  /**
+   * Innocuous output when an image data URI fails escaping.
+   *
+   * <p>When escaper fails, we need to return something that is both clearly an image, but clearly
+   * invalid. We don't want the browser to fetch anything. We also don't necessarily want a
+   * transparent gif, since it doesn't alert developers to an issue. And finally, by not starting
+   * with GIF89a, we ensure the browser doesn't attempt to actually decode it and crash.
+   *
+   * <p>Based on {@link
+   * com.google.template.soy.shared.restricted.EscapingConventions.FilterImageDataUri}.
+   */
+  static String IMAGE_URI_INNOCUOUS_OUTPUT = "data:image/gif;base64,zSoyz";
+
+  /**
+   * Innocuous output when a URI fails escaping.
+   *
+   * <p>about:invalid is registered in http://www.w3.org/TR/css3-values/#about-invalid: "The
+   * about:invalid URI references a non-existent document with a generic error condition. It can be
+   * used when a URI is necessary, but the default value shouldn't be resolveable as any type of
+   * document."
+   *
+   * <p>Based on {@link
+   * com.google.template.soy.shared.restricted.EscapingConventions.FilterNormalizeUri}.
+   */
+  static String NORMAL_URI_INNOCUOUS_OUTPUT = "about:invalid#zSoyz";
+}