Spellcheck : Fix caching in cases where text is deleted.

components/spellcheck/renderer/spellcheck_provider.cc

 // Copyright (c) 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/spellcheck/renderer/spellcheck_provider.h"
 
 #include "base/command_line.h"
 #include "base/metrics/histogram_macros.h"
 #include "components/spellcheck/common/spellcheck_marker.h"
 #include "components/spellcheck/common/spellcheck_messages.h"
@@ skipping 311 matching lines @@
   // substring of the cached text.
   if (text_length < last_length &&
       !last_request_.compare(0, text_length, request)) {
     size_t result_size = 0;
     for (size_t i = 0; i < last_results_.size(); ++i) {
       size_t start = last_results_[i].location;
       size_t end = start + last_results_[i].length;
       if (start <= text_length && end <= text_length)
         ++result_size;
     }
-    if (result_size > 0) {
-      blink::WebVector<blink::WebTextCheckingResult> results(result_size);
-      for (size_t i = 0; i < result_size; ++i) {
-        results[i].decoration = last_results_[i].decoration;
-        results[i].location = last_results_[i].location;
-        results[i].length = last_results_[i].length;
-        results[i].replacement = last_results_[i].replacement;
-      }
-      completion->didFinishCheckingText(results);
-      return true;
+    blink::WebVector<blink::WebTextCheckingResult> results(result_size);

[groby-ooo-7-16, 2016/11/15 19:36:57]

So, I might be misreading this, but it looks to me like a shorter approach is

blink::WebVector<...> results (last_results_.data(), result_size);

While you're here :)

[timvolodine, 2016/11/17 20:53:15]

Yes much more compact indeed.
Done.

+    for (size_t i = 0; i < result_size; ++i) {
+      results[i].decoration = last_results_[i].decoration;
+      results[i].location = last_results_[i].location;
+      results[i].length = last_results_[i].length;
+      results[i].replacement = last_results_[i].replacement;
     }
+    completion->didFinishCheckingText(results);
+    return true;

[groby-ooo-7-16, 2016/11/15 19:36:57]

I don't think this works as intended. SatisfyRequestFromCache is only supposed
to invoke the completion/return true when result_size != 0

Is that causing the issues that you're fixing? (Essentially, I don't understand
how this change fixes the problems you mention)

[timvolodine, 2016/11/17 20:53:15]

So currently a substring without misspellings will result in cache miss, this is
what this patch is fixing.
I've added a SpellCheckProviderCacheTest.SubstringWithoutMisspellings to
illustrate.

   }
 
   return false;
 }
 
 void SpellCheckProvider::OnDestruct() {
   delete this;
 }