Fix b180514: Some exception entries cannot be deleted from a setting panel.

This bug is caused by single trailing dot trimming from the input.
Fixed it by forbidding a pattern if canonicalization is not idempotent, i.e. the pattern canonicalized twice differs from the pattern canonicalized once.

BUG=180514


Review URL: https://chromiumcodereview.appspot.com/13251012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@192984 0039d316-1c4b-4281-b951-d872f2087c98

chrome/common/content_settings_pattern.cc

@@ -156,6 +156,20 @@ ContentSettingsPattern ContentSettingsPattern::Builder::Build() {
   } else {
     is_valid_ = Validate(parts_);
   }
+  if (!is_valid_)
+    return ContentSettingsPattern();
+
+  // A pattern is invalid if canonicalization is not idempotent.
+  // This check is here because it should be checked no matter
+  // use_legacy_validate_ is.
+  PatternParts parts(parts_);
+  if (!Canonicalize(&parts))
+    return ContentSettingsPattern();
+  if (ContentSettingsPattern(parts_, true) !=
+      ContentSettingsPattern(parts, true)) {
+    return ContentSettingsPattern();
+  }
+
   return ContentSettingsPattern(parts_, is_valid_);
 }
 

chrome/common/content_settings_pattern_unittest.cc

@@ -206,6 +206,9 @@ TEST(ContentSettingsPatternTest, TrimEndingDotFromHost) {
                Pattern("www.example.com.").ToString().c_str());
 
   EXPECT_TRUE(Pattern("www.example.com.") == Pattern("www.example.com"));
+
+  EXPECT_TRUE(Pattern(".").IsValid());
+  EXPECT_STREQ(".", Pattern(".").ToString().c_str());
 }
 
 TEST(ContentSettingsPatternTest, FromString_WithNoWildcards) {
@@ -443,6 +446,10 @@ TEST(ContentSettingsPatternTest, InvalidPatterns) {
   EXPECT_STREQ("", Pattern("file://").ToString().c_str());
   EXPECT_FALSE(Pattern("file:///foo/bar.html:8080").IsValid());
   EXPECT_STREQ("", Pattern("file:///foo/bar.html:8080").ToString().c_str());
+
+  // Host having multiple ending dots.
+  EXPECT_FALSE(Pattern("www.example.com..").IsValid());
+  EXPECT_STREQ("", Pattern("www.example.com..").ToString().c_str());
 }
 
 TEST(ContentSettingsPatternTest, UnequalOperator) {