TabPrinter: Verify the tab's state before printing

TabPrinter: Verify the tab's state before printing

If the tab is instructed to print while the native side is not properly
initialized, it will now fail gracefully instead of crashing.

BUG=445467
Committed: https://crrev.com/c8076545db7f1d26298be68c1a278ff9b78ad343
Cr-Commit-Position: refs/heads/master@{#311347}

[dgn, 2015-01-13 21:24:56]

dgn@chromium.org changed reviewers:
+ tedchoc@chromium.org

[dgn, 2015-01-13 21:24:57]

I did not manage to reproduce the issue, so I guess this will do.

https://codereview.chromium.org/837773008/diff/1/chrome/android/java/src/org/...
File
chrome/android/java/src/org/chromium/chrome/browser/printing/TabPrinter.java
(right):

https://codereview.chromium.org/837773008/diff/1/chrome/android/java/src/org/...
chrome/android/java/src/org/chromium/chrome/browser/printing/TabPrinter.java:42:
if (tab == null) return sDefaultTitle;
I could also have checked it here, but the worst that can happen is an null
string would be returned. Then the outcome is the same.

[Ted C, 2015-01-13 21:30:19]

lgtm

[dgn, 2015-01-13 21:35:41]

The CQ bit was checked by dgn@chromium.org

[commit-bot: I haz the power, 2015-01-13 21:36:51]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/837773008/1

[commit-bot: I haz the power, 2015-01-13 22:27:55]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-01-13 22:28:39]

Patchset 1 (id:??) landed as
https://crrev.com/c8076545db7f1d26298be68c1a278ff9b78ad343
Cr-Commit-Position: refs/heads/master@{#311347}