Add/remove spell checking markers in text inputs depending on focus.

Source/core/editing/SpellChecker.h

Index: Source/core/editing/SpellChecker.h
diff --git a/Source/core/editing/SpellChecker.h b/Source/core/editing/SpellChecker.h
index 44a6b5a5c84d26b41eb3df6048d516b9fe98d584..9cc37715aa6b68869df75cd97960b77a77beb3c3 100644
--- a/Source/core/editing/SpellChecker.h
+++ b/Source/core/editing/SpellChecker.h
@@ -83,6 +83,7 @@ public:
 
     void requestCheckingFor(PassRefPtr<SpellCheckRequest>);
     void cancelCheck();
+    void cancelProcessingRequest();

[please use gerrit instead, 2013/07/30 21:32:00]

Can you reuse cancelCheck() instead? The implementation seems to be doing
exactly same task. If you think that implementation of cancelProcessingRequest()
is better, you can try modifying cancelCheck() implementation instead. We have
layout tests and unit tests in place to make sure your modifications don't break
spellchecker. You're already familiar with the layout tests:
LayoutTest/editing/spelling. You can run Blink's spellcheck unit tests like so:

  ./out/Release/webkit_unit_tests --gtest_filter="*Spell*:*spell*"

[pstanek, 2013/07/30 21:50:39]

This is something layout tests showed me as in the original patch I was using
cancelCheck(). The problem was that if some checks were added to the queue
before unfocusing an input they were also cancelled causing spellcheck-queue
test to fail. This is why I created this function to cancel only the current
request. I could reuse cancelCheck() however by adding an extra param to it.

 
     int lastRequestSequence() const
     {