Make WebSpellCheckClient aware of leak detection

third_party/WebKit/Source/core/editing/spellcheck/SpellCheckRequester.cpp

Index: third_party/WebKit/Source/core/editing/spellcheck/SpellCheckRequester.cpp
diff --git a/third_party/WebKit/Source/core/editing/spellcheck/SpellCheckRequester.cpp b/third_party/WebKit/Source/core/editing/spellcheck/SpellCheckRequester.cpp
index b467afaaf9a5dce66073caab7635b909f2a04227..b8b43532f7a9d24b2ae0c488d48bfb1b5c6eca17 100644
--- a/third_party/WebKit/Source/core/editing/spellcheck/SpellCheckRequester.cpp
+++ b/third_party/WebKit/Source/core/editing/spellcheck/SpellCheckRequester.cpp
@@ -229,6 +229,10 @@ void SpellCheckRequester::prepareForLeakDetection()
     // the leak detector, they're all cancelled to prevent flaky leaks being
     // reported.
     m_requestQueue.clear();
+    // WebSpellCheckClient stores a set of WebTextCheckingCompletion objects,
+    // which may store references to already invoked requests. We should clear
+    // these references to prevent them from being a leak source.
+    client().cancelAllPendingRequests();
 }
 
 void SpellCheckRequester::invokeRequest(SpellCheckRequest* request)