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

chrome/common/content_settings_pattern.cc

Index: chrome/common/content_settings_pattern.cc
diff --git a/chrome/common/content_settings_pattern.cc b/chrome/common/content_settings_pattern.cc
index 98ac6d637e2e52cae9ba9d582122e3d724e53dd6..9153de66ae7d151c95eb51c4def98cfb6a7b6a87 100644
--- a/chrome/common/content_settings_pattern.cc
+++ b/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_);
 }