Add checks for android printing

chrome/android/java/src/org/chromium/chrome/browser/printing/TabPrinter.java

Index: chrome/android/java/src/org/chromium/chrome/browser/printing/TabPrinter.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/printing/TabPrinter.java b/chrome/android/java/src/org/chromium/chrome/browser/printing/TabPrinter.java
index 94d084997c202a664edbe39288961dd2b40509fd..d8644a61b1f1368cb07727297dda7d63b582f405 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/printing/TabPrinter.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/printing/TabPrinter.java
@@ -6,6 +6,7 @@
 
 import android.text.TextUtils;
 
+import org.chromium.base.Log;
 import org.chromium.chrome.browser.tab.Tab;
 import org.chromium.printing.Printable;
 
@@ -19,6 +20,7 @@
  */
 public class TabPrinter implements Printable {
     private static String sDefaultTitle;
+    private static final String TAG = "cr.printing";
 
     private final WeakReference<Tab> mTab;
 
@@ -33,7 +35,11 @@ public static void setDefaultTitle(String defaultTitle) {
     @Override
     public boolean print() {
         Tab tab = mTab.get();
-        return tab != null && tab.isInitialized() && tab.print();
+        if (tab == null || !tab.isInitialized()) {
+            Log.d(TAG, "Tab not ready, unable to start printing.");
+            return false;
+        }
+        return tab.print();
     }
 
     @Override