diff --git a/mobile/android/base/Tab.java b/mobile/android/base/Tab.java
index 62379369af1..9ee563fe293 100644
--- a/mobile/android/base/Tab.java
+++ b/mobile/android/base/Tab.java
@@ -263,7 +263,7 @@ public final class Tab {
     }
 
     public void setContentType(String contentType) {
-        mContentType = contentType;
+        mContentType = (contentType == null) ? "" : contentType;
     }
 
     public String getContentType() {
diff --git a/mobile/android/chrome/content/browser.js b/mobile/android/chrome/content/browser.js
index 930e856fb37..c97f66a4afc 100644
--- a/mobile/android/chrome/content/browser.js
+++ b/mobile/android/chrome/content/browser.js
@@ -3231,7 +3231,7 @@ Tab.prototype = {
         tabID: this.id,
         uri: fixedURI.spec,
         documentURI: documentURI,
-        contentType: contentType,
+        contentType: (contentType ? contentType : ""),
         sameDocument: sameDocument
       }
     };