Fix favicon updating in document mode.

chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappActivity.java

Index: chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappActivity.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappActivity.java b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappActivity.java
index 7ebc2da4365a870f782680d2f558c135d54f6fd6..a2fdd312582db9a49bde32a97a06a02642159d26 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappActivity.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappActivity.java
@@ -320,6 +320,7 @@ public class WebappActivity extends FullScreenActivity {
                 if (!isWebappDomain()) return;
                 // No need to cache the favicon if there is an icon declared in app manifest.
                 if (mWebappInfo.icon() != null) return;
+                if (icon == null) return;
                 if (mLargestFavicon == null || icon.getWidth() > mLargestFavicon.getWidth()
                         || icon.getHeight() > mLargestFavicon.getHeight()) {
                     mLargestFavicon = icon;