Clear SDCH information on "Clear browsing data" path.

chrome/browser/net/sdch_dictionary_fetcher.cc

Index: chrome/browser/net/sdch_dictionary_fetcher.cc
diff --git a/chrome/browser/net/sdch_dictionary_fetcher.cc b/chrome/browser/net/sdch_dictionary_fetcher.cc
index 1130fe336242b5b5c666a2ae433771e1b98d3bd4..0a838bd37fa9adb86be501707f81888b9f30e66b 100644
--- a/chrome/browser/net/sdch_dictionary_fetcher.cc
+++ b/chrome/browser/net/sdch_dictionary_fetcher.cc
@@ -49,6 +49,16 @@ void SdchDictionaryFetcher::Schedule(const GURL& dictionary_url) {
   ScheduleDelayedRun();
 }
 
+void SdchDictionaryFetcher::Cancel() {
+  DCHECK(CalledOnValidThread());
+
+  while (!fetch_queue_.empty())
+    fetch_queue_.pop();
+  attempted_load_.clear();
+  weak_factory_.InvalidateWeakPtrs();
+  current_fetch_.reset(NULL);
+}
+
 void SdchDictionaryFetcher::ScheduleDelayedRun() {
   if (fetch_queue_.empty() || current_fetch_.get() || task_is_pending_)
     return;
@@ -64,6 +74,10 @@ void SdchDictionaryFetcher::StartFetching() {
   DCHECK(task_is_pending_);
   task_is_pending_ = false;
 
+  // Handle losing the race against Cancel().
+  if (fetch_queue_.empty())
+    return;
+
   DCHECK(context_.get());
   current_fetch_.reset(net::URLFetcher::Create(
       fetch_queue_.front(), net::URLFetcher::GET, this));