Check and canonicalize CSS selectors before registering PageStateMatchers.

chrome/renderer/extensions/css_native_handler.cc

+// Copyright 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/extensions/css_native_handler.h"
+
+#include "chrome/renderer/extensions/chrome_v8_context.h"
+#include "third_party/WebKit/public/platform/WebString.h"
+#include "third_party/WebKit/public/web/WebScriptBindings.h"
+#include "third_party/WebKit/public/web/WebSelector.h"
+
+namespace extensions {
+
+using WebKit::WebString;
+
+CssNativeHandler::CssNativeHandler(ChromeV8Context* context)
+    : ObjectBackedNativeHandler(context) {
+  RouteFunction("CanonicalizeCompoundSelector",
+                base::Bind(&CssNativeHandler::CanonicalizeCompoundSelector,
+                           base::Unretained(this)));
+}
+
+void CssNativeHandler::CanonicalizeCompoundSelector(
+    const v8::FunctionCallbackInfo<v8::Value>& args) {
+  CHECK_EQ(args.Length(), 1);
+  CHECK(args[0]->IsString());
+  WebString input_selector =
+      WebKit::WebScriptBindings::toWebString(args[0].As<v8::String>());
+  WebString output_selector = WebKit::canonicalizeSelector(

[not at google - send to devlin, 2013/08/29 22:24:04]

I presume from reading the JS that this returns an empty string if it's invalid
CSS. maybe you should comment that.

[Jeffrey Yasskin, 2013/08/29 23:18:49]

It's commented in third_party/WebKit/public/web/WebSelector.h and in
css_native_handler.h. Do I need it in a third place?

[not at google - send to devlin, 2013/08/29 23:24:29]

I didn't see it in the header file and :O webkit has a comment?

+      input_selector, WebKit::WebSelectorTypeCompound);
+  args.GetReturnValue().Set(WebKit::WebScriptBindings::toV8String(
+      output_selector, context()->v8_context()->GetIsolate()));
+}
+
+}  // namespace extensions