Merge 211197 "Handle null char in the middle of text in custom s..."

A second attempt to merge this CL into M28 (branch 1500). This time with
utf_string_conversions.h include. Lack of this include blocked the previous
attempt to merge.

> Handle null char in the middle of text in custom spellcheck dictionary engine
> 
> The code in custom spellcheck dictionary erroneously assumes that null char
> terminates the string. Other code does not make this assumption, however, and
> passes misspelling offsets to custom spellcheck dictionary that are past the
> position of the null char. This causes an exception. The fix is to not convert
> the string into a char array and then back into a string in custom spellcheck
> dictionary engine.
> 
> TEST=CustomDictionaryTest.HandlesNullCharacters
> TEST=CustomDictionaryTest.HandlesEmptyWordWithInvalidSubstring
> BUG=258550
> 
> Review URL: https://chromiumcodereview.appspot.com/18137008

TBR=rouslan@chromium.org

Review URL: https://codereview.chromium.org/19278019

git-svn-id: svn://svn.chromium.org/chrome/branches/1500/src@211847 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 24 insertions, 13 deletions

diff --git a/chrome/renderer/spellchecker/custom_dictionary_engine.cc b/chrome/renderer/spellchecker/custom_dictionary_engine.cc
index 06c4abd..35e1acf 100644
--- a/chrome/renderer/spellchecker/custom_dictionary_engine.cc
+++ b/chrome/renderer/spellchecker/custom_dictionary_engine.cc
@@ -42,18 +42,14 @@ void CustomDictionaryEngine::OnCustomDictionaryChanged(
 }
 
 bool CustomDictionaryEngine::SpellCheckWord(
-    const char16* text,
+    const string16& text,
     int misspelling_start,
     int misspelling_len) {
-  DCHECK(text);
-  string16 text16(text);
-
   // The text to be checked is empty on OSX(async) right now.
   // TODO(groby): Fix as part of async hook-up. (http://crbug.com/178241)
-  if (text16.empty())
-    return false;
-  DCHECK(text16.length() >= size_t(misspelling_start + misspelling_len));
-  return misspelling_start >= 0 &&
+  return
+      misspelling_start >= 0 &&
       misspelling_len > 0 &&
-      dictionary_.count(text16.substr(misspelling_start, misspelling_len)) > 0;
+      size_t(misspelling_start + misspelling_len) <= text.length() &&
+      dictionary_.count(text.substr(misspelling_start, misspelling_len)) > 0;
 }
diff --git a/chrome/renderer/spellchecker/custom_dictionary_engine.h b/chrome/renderer/spellchecker/custom_dictionary_engine.h
index d2dc8ca..d24bdb4 100644
--- a/chrome/renderer/spellchecker/custom_dictionary_engine.h
+++ b/chrome/renderer/spellchecker/custom_dictionary_engine.h
@@ -25,7 +25,7 @@ class CustomDictionaryEngine {
   // Spellcheck |text|. Assumes that another spelling engine has set
   // |misspelling_start| and |misspelling_len| to indicate a misspelling.
   // Returns true if there are no misspellings, otherwise returns false.
-  bool SpellCheckWord(const char16* text,
+  bool SpellCheckWord(const string16& text,
                       int misspelling_start,
                       int misspelling_len);
 
diff --git a/chrome/renderer/spellchecker/custom_dictionary_engine_unittest.cc b/chrome/renderer/spellchecker/custom_dictionary_engine_unittest.cc
index 440d110..986e67c 100644
--- a/chrome/renderer/spellchecker/custom_dictionary_engine_unittest.cc
+++ b/chrome/renderer/spellchecker/custom_dictionary_engine_unittest.cc
@@ -1,8 +1,9 @@
 // Copyright (c) 2013 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 "chrome/renderer/spellchecker/custom_dictionary_engine.h"
 
+#include "base/strings/utf_string_conversions.h"
+#include "chrome/renderer/spellchecker/custom_dictionary_engine.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 TEST(CustomDictionaryTest, HandlesEmptyWordWithInvalidSubstring) {
@@ -13,3 +14,16 @@ TEST(CustomDictionaryTest, HandlesEmptyWordWithInvalidSubstring) {
   EXPECT_FALSE(engine.SpellCheckWord(string16().c_str(), 15, 23));
 }
 
+TEST(CustomDictionaryTest, Basic) {
+  CustomDictionaryEngine engine;
+  EXPECT_FALSE(engine.SpellCheckWord(ASCIIToUTF16("helllo").c_str(), 0, 6));
+  std::set<std::string> custom_words;
+  custom_words.insert("helllo");
+  engine.Init(custom_words);
+  EXPECT_TRUE(engine.SpellCheckWord(ASCIIToUTF16("helllo").c_str(), 0, 6));
+}
+
+TEST(CustomDictionaryTest, HandlesNullCharacters) {
+  char16 data[4] = {'a', 0, 'b', 'c'};
+  EXPECT_FALSE(CustomDictionaryEngine().SpellCheckWord(data, 1, 1));
+}
diff --git a/chrome/renderer/spellchecker/spellcheck.cc b/chrome/renderer/spellchecker/spellcheck.cc
index b12e5b7..57108f6 100644
--- a/chrome/renderer/spellchecker/spellcheck.cc
+++ b/chrome/renderer/spellchecker/spellcheck.cc
@@ -223,7 +223,7 @@ bool SpellCheck::SpellCheckParagraph(
     }
 
     if (!custom_dictionary_.SpellCheckWord(
-            &text[offset], misspelling_start, misspelling_length)) {
+            text, misspelling_start + offset, misspelling_length)) {
       string16 replacement;
       textcheck_results.push_back(WebTextCheckingResult(
           WebKit::WebTextCheckingTypeSpelling,
@@ -368,7 +368,8 @@ void SpellCheck::CreateTextCheckingResults(
         type = WebKit::WebTextCheckingTypeGrammar;
       }
     }
-    if (!custom_dictionary_.SpellCheckWord(text, word_location, word_length)) {
+    if (!custom_dictionary_.SpellCheckWord(
+            line_text, word_location, word_length)) {
       list.push_back(WebTextCheckingResult(
           type,
           word_location + line_offset,