diff --git a/pom.xml b/pom.xml
index 6fed2842..c2b47072 100644
--- a/pom.xml
+++ b/pom.xml
@@ -80,7 +80,7 @@
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
     <java.version>1.7</java.version>
-    <guava.version>19.0</guava.version>
+    <guava.version>20.0</guava.version>
   </properties>
 
   <build>
@@ -186,7 +186,7 @@
     <dependency>  <!-- For com.google.debugging.sourcemap -->
       <groupId>com.google.javascript</groupId>
       <artifactId>closure-compiler-unshaded</artifactId>
-      <version>v20160713</version>
+      <version>v20170218</version>
     </dependency>
 
     <dependency>
diff --git a/src/com/google/common/css/JobDescription.java b/src/com/google/common/css/JobDescription.java
index f9c94e2e..8c1c4fec 100644
--- a/src/com/google/common/css/JobDescription.java
+++ b/src/com/google/common/css/JobDescription.java
@@ -25,7 +25,6 @@
 import java.util.Map;
 import java.util.Set;
 
-
 /**
  * Provides inputs and options to Closure Stylesheets.
  * To construct an instance, use a {@link JobDescriptionBuilder}.
@@ -69,6 +68,7 @@ public class JobDescription {
   public final Map<String, Integer> compileConstants;
   public final boolean createSourceMap;
   public final SourceMapDetailLevel sourceMapLevel;
+  public final boolean sourceMapIncludeContent;
   public final boolean preserveImportantComments;
 
   static final String CONDITION_FOR_LTR = "GSS_LTR";
@@ -142,6 +142,7 @@ public enum SourceMapDetailLevel { ALL, DEFAULT }
       boolean suppressDependencyCheck, Map<String, Integer> compileConstants,
       boolean createSourceMap,
       SourceMapDetailLevel sourceMapLevel,
+      boolean sourceMapIncludeContent,
       boolean preserveImportantComments) {
     this.allowUndefinedConstants = allowUndefinedConstants;
     Preconditions.checkArgument(!inputs.contains(null));
@@ -190,6 +191,7 @@ public enum SourceMapDetailLevel { ALL, DEFAULT }
     this.compileConstants = ImmutableMap.copyOf(compileConstants);
     this.createSourceMap = createSourceMap;
     this.sourceMapLevel = sourceMapLevel;
+    this.sourceMapIncludeContent = sourceMapIncludeContent;
     this.preserveImportantComments = preserveImportantComments;
   }
 
diff --git a/src/com/google/common/css/JobDescriptionBuilder.java b/src/com/google/common/css/JobDescriptionBuilder.java
index 0f4a9d5e..9132a250 100644
--- a/src/com/google/common/css/JobDescriptionBuilder.java
+++ b/src/com/google/common/css/JobDescriptionBuilder.java
@@ -75,6 +75,7 @@ public class JobDescriptionBuilder {
   JobDescription job = null;
   boolean createSourceMap;
   SourceMapDetailLevel sourceMapLevel;
+  boolean sourceMapIncludeContent;
 
   public JobDescriptionBuilder() {
     this.inputs = Lists.newArrayList();
@@ -111,6 +112,7 @@ public JobDescriptionBuilder() {
     this.compileConstants = new HashMap<>();
     this.createSourceMap = false;
     this.sourceMapLevel = SourceMapDetailLevel.DEFAULT;
+    this.sourceMapIncludeContent = false;
     this.preserveImportantComments = false;
   }
 
@@ -151,6 +153,7 @@ public JobDescriptionBuilder copyFrom(JobDescription jobToCopy) {
     setCompileConstants(jobToCopy.compileConstants);
     this.createSourceMap = jobToCopy.createSourceMap;
     this.sourceMapLevel = jobToCopy.sourceMapLevel;
+    this.sourceMapIncludeContent = jobToCopy.sourceMapIncludeContent;
     this.preserveImportantComments = jobToCopy.preserveImportantComments;
     return this;
   }
@@ -495,7 +498,8 @@ public JobDescription getJobDescription() {
         gssFunctionMapProvider, cssSubstitutionMapProvider,
         outputRenamingMapFormat, inputRenamingMap, preserveComments,
         suppressDependencyCheck, compileConstants,
-        createSourceMap, sourceMapLevel, preserveImportantComments);
+        createSourceMap, sourceMapLevel, sourceMapIncludeContent,
+        preserveImportantComments);
     return job;
   }
 
@@ -509,4 +513,8 @@ public JobDescriptionBuilder setCreateSourceMap(boolean createSourceMap) {
     return this;
   }
 
+  public JobDescriptionBuilder setSourceMapIncludeContent(boolean sourceMapIncludeContent) {
+    this.sourceMapIncludeContent = sourceMapIncludeContent;
+    return this;
+  }
 }
diff --git a/src/com/google/common/css/compiler/commandline/ClosureCommandLineCompiler.java b/src/com/google/common/css/compiler/commandline/ClosureCommandLineCompiler.java
index 48eac76e..9630626e 100644
--- a/src/com/google/common/css/compiler/commandline/ClosureCommandLineCompiler.java
+++ b/src/com/google/common/css/compiler/commandline/ClosureCommandLineCompiler.java
@@ -145,6 +145,11 @@ static class Flags {
         + "mappings, and ALL, which outputs mappings for all elements.")
     private SourceMapDetailLevel sourceMapLevel = SourceMapDetailLevel.DEFAULT;
 
+    @Option(name = "--source_map_include_content", usage = "Includes sources "
+        + "content into source map. Greatly increases the size of source maps "
+        + "but offers greater portability (default: false)")
+    private boolean sourceMapIncludeContent = false;
+
     @Option(name = "--copyright-notice",
         usage = "Copyright notice to prepend to the output")
     private String copyrightNotice = null;
@@ -259,6 +264,7 @@ JobDescription createJobDescription() {
           getGssFunctionMapProviderForName(gssFunctionMapProviderClassName);
       builder.setGssFunctionMapProvider(gssFunctionMapProvider);
       builder.setSourceMapLevel(sourceMapLevel);
+      builder.setSourceMapIncludeContent(sourceMapIncludeContent);
       builder.setCreateSourceMap(!Strings.isNullOrEmpty(sourceMapFile));
 
       if (inputRenamingMapFileName != null) {
diff --git a/src/com/google/common/css/compiler/commandline/DefaultCommandLineCompiler.java b/src/com/google/common/css/compiler/commandline/DefaultCommandLineCompiler.java
index 9126e22d..4e30f88f 100644
--- a/src/com/google/common/css/compiler/commandline/DefaultCommandLineCompiler.java
+++ b/src/com/google/common/css/compiler/commandline/DefaultCommandLineCompiler.java
@@ -81,7 +81,7 @@ private GssSourceMapGenerator createSourceMapGenerator(JobDescription job) {
     if (!job.createSourceMap) {
       return new NullGssSourceMapGenerator();
     }
-    return new DefaultGssSourceMapGenerator(job.sourceMapLevel);
+    return new DefaultGssSourceMapGenerator(job.sourceMapLevel, job.sourceMapIncludeContent);
   }
 
   /**
diff --git a/src/com/google/common/css/compiler/passes/DefaultGssSourceMapGenerator.java b/src/com/google/common/css/compiler/passes/DefaultGssSourceMapGenerator.java
index d81177a3..27d2cc22 100644
--- a/src/com/google/common/css/compiler/passes/DefaultGssSourceMapGenerator.java
+++ b/src/com/google/common/css/compiler/passes/DefaultGssSourceMapGenerator.java
@@ -89,6 +89,8 @@ static class Mapping {
 
   private SourceMapDetailLevel sourceMapDetailLevel;
 
+  private boolean sourceMapIncludeContent;
+
   /** Predicate to determine whether to include current node under visit into {@code mappings}. **/
   private Predicate<CssNode> detailLevelPredicate;
 
@@ -96,13 +98,16 @@ static class Mapping {
    * Constructor to get source map class to use.
    *
    * @param sourceMapDetailLevel used to control the output details of source map
+   * @param sourceMapIncludeContent used to include content in source map
    */
-  public DefaultGssSourceMapGenerator(SourceMapDetailLevel sourceMapDetailLevel) {
+  public DefaultGssSourceMapGenerator(SourceMapDetailLevel sourceMapDetailLevel,
+      boolean sourceMapIncludeContent) {
     Preconditions.checkState(sourceMapDetailLevel != null);
     this.mappings = new ArrayDeque<>();
     this.generator = SourceMapGeneratorFactory.getInstance(SourceMapFormat.V3);
     this.allMappings = new ArrayList<>();
     this.sourceMapDetailLevel = sourceMapDetailLevel;
+    this.sourceMapIncludeContent = sourceMapIncludeContent;
     this.detailLevelPredicate = DETAIL_LEVEL_PREDICATES.get(this.sourceMapDetailLevel);
   }
 
@@ -202,12 +207,18 @@ private void generateSourceMap() {
           completeMapping.sourceFile, null,
           completeMapping.inputStart,
           completeMapping.outputStart, completeMapping.outputEnd);
+
+      if (sourceMapIncludeContent) {
+        generator.addSourcesContent(
+            completeMapping.sourceFile, completeMapping.sourceContents);
+      }
     }
   }
 
 
   private static final class CompleteMapping implements Comparable<CompleteMapping> {
     final String sourceFile;
+    final String sourceContents;
     final FilePosition inputStart;
     final FilePosition outputStart;
     final FilePosition outputEnd;
@@ -215,6 +226,7 @@ private static final class CompleteMapping implements Comparable<CompleteMapping
     CompleteMapping(Mapping mapping) {
       CssNode node = mapping.node;
       this.sourceFile = getSourceFileName(node);
+      this.sourceContents = getSourceFileContents(node);
       this.inputStart = new FilePosition(
           getStartLineno(node), getStartCharIndex(node));
       this.outputStart = mapping.start;
@@ -237,6 +249,13 @@ private static String getSourceFileName(CssNode node) {
       return node.getSourceCodeLocation().getSourceCode().getFileName();
     }
 
+    /**
+     * Gets the source file contents for current node.
+     */
+    private static String getSourceFileContents(CssNode node) {
+      return node.getSourceCodeLocation().getSourceCode().getFileContents();
+    }
+
     /**
      * Gets the start line index in the source code of {@code node} adjusted to 0-based indices.
      *
diff --git a/tests/com/google/common/css/compiler/ast/testing/TestParser.java b/tests/com/google/common/css/compiler/ast/testing/TestParser.java
index 6b5f0a54..edb5fe39 100644
--- a/tests/com/google/common/css/compiler/ast/testing/TestParser.java
+++ b/tests/com/google/common/css/compiler/ast/testing/TestParser.java
@@ -47,7 +47,7 @@ public class TestParser {
   private List<SourceCode> sources = new ArrayList<>();
   private TestErrorManager errorManager = new TestErrorManager(new String[0]);
   private GssSourceMapGenerator generator =
-      new DefaultGssSourceMapGenerator(SourceMapDetailLevel.ALL);
+      new DefaultGssSourceMapGenerator(SourceMapDetailLevel.ALL, true);
   private String output = null;
   private SourceMapping sourceMap = null;
   private String sourceMapString = null;