Don't handle DCHECK failure.

components/webdata/common/web_data_request_manager.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/webdata/common/web_data_request_manager.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/location.h"
@@ skipping 86 matching lines @@
 }
 
 int WebDataRequestManager::GetNextRequestHandle() {
   base::AutoLock l(pending_lock_);
   return ++next_request_handle_;
 }
 
 void WebDataRequestManager::CancelRequest(WebDataServiceBase::Handle h) {
   base::AutoLock l(pending_lock_);
   RequestMap::iterator i = pending_requests_.find(h);
-  if (i == pending_requests_.end()) {
-    NOTREACHED() << "Canceling a nonexistent web data service request";
-    return;
-  }
+  DCHECK(i != pending_requests_.end());
   i->second->Cancel();
   pending_requests_.erase(i);
 }
 
 void WebDataRequestManager::RequestCompleted(
     std::unique_ptr<WebDataRequest> request) {
   scoped_refptr<base::SingleThreadTaskRunner> task_runner =
       request->GetTaskRunner();
   task_runner->PostTask(
       FROM_HERE, base::Bind(&WebDataRequestManager::RequestCompletedOnThread,
                             this, base::Passed(&request)));
 }
 
 void WebDataRequestManager::RequestCompletedOnThread(
     std::unique_ptr<WebDataRequest> request) {
   if (request->IsCancelled())
     return;
 
   // TODO(robliao): Remove ScopedTracker below once https://crbug.com/422460 is
   // fixed.
   tracked_objects::ScopedTracker tracking_profile1(
       FROM_HERE_WITH_EXPLICIT_FUNCTION(
           "422460 WebDataRequestManager::RequestCompletedOnThread::UpdateMap"));
   {
     base::AutoLock l(pending_lock_);
     RequestMap::iterator i = pending_requests_.find(request->GetHandle());
-    if (i == pending_requests_.end()) {
-      NOTREACHED() << "Request completed called for an unknown request";
-      return;
-    }
+    DCHECK(i != pending_requests_.end());
 
     // Take ownership of the request object and remove it from the map.
     pending_requests_.erase(i);
   }
 
   // TODO(robliao): Remove ScopedTracker below once https://crbug.com/422460 is
   // fixed.
   tracked_objects::ScopedTracker tracking_profile2(
       FROM_HERE_WITH_EXPLICIT_FUNCTION(
           "422460 "
           "WebDataRequestManager::RequestCompletedOnThread::NotifyConsumer"));
 
   // Notify the consumer if needed.
   if (!request->IsCancelled()) {
     WebDataServiceConsumer* consumer = request->GetConsumer();
     request->OnComplete();
     if (consumer) {
       std::unique_ptr<WDTypedResult> r = request->GetResult();
       consumer->OnWebDataServiceRequestDone(request->GetHandle(), r.get());
     }
   }
 
 }