Check and canonicalize CSS selectors before registering PageStateMatchers.

chrome/browser/extensions/api/declarative_content/declarative_content_apitest.cc

Index: chrome/browser/extensions/api/declarative_content/declarative_content_apitest.cc
diff --git a/chrome/browser/extensions/api/declarative_content/declarative_content_apitest.cc b/chrome/browser/extensions/api/declarative_content/declarative_content_apitest.cc
index c75431674f92be195e45fe94f9edd36926abc379..60d84b4b371a905b74c8f3a6d5f860b601a0b4d9 100644
--- a/chrome/browser/extensions/api/declarative_content/declarative_content_apitest.cc
+++ b/chrome/browser/extensions/api/declarative_content/declarative_content_apitest.cc
@@ -109,5 +109,54 @@ IN_PROC_BROWSER_TEST_F(DeclarativeContentApiTest, Overview) {
   EXPECT_FALSE(page_action->GetIsVisible(tab_id));
 }
 
+IN_PROC_BROWSER_TEST_F(DeclarativeContentApiTest,
+                       CanonicalizesPageStateMatcherCss) {
+  ext_dir_.WriteManifest(kDeclarativeContentManifest);
+  ext_dir_.WriteFile(
+      FILE_PATH_LITERAL("background.js"),
+      "var declarative = chrome.declarative;\n"
+      "\n"
+      "var PageStateMatcher = chrome.declarativeContent.PageStateMatcher;\n"
+      "\n"
+      "chrome.test.runTests([\n"
+      "  function canonicalizesCss() {\n"
+      "    var psm = new PageStateMatcher(\n"

[Jeffrey Yasskin, 2013/08/26 22:35:19]

I ought to be able to run these tests entirely on the renderer side, but I don't
see a simple way to import the chrome.declarativeContent definitions.

[not at google - send to devlin, 2013/08/27 01:46:14]

Given we have no way to spin up a fake webkit instance with content (at least
yet), which the functionality heavily depends on (.. it's CSS), it would be a
lot of work for this.

Incidentally there's still something to be said for writing actual extensions
here. It's quite hard to read JS strings embedded in C++ like this. Fine for a
few lines of code, but this is getting meaty.

[Jeffrey Yasskin, 2013/08/27 19:09:48]

There's something to be said, but it tends to take me a lot longer to understand
tests that are split between C++ code and a separate extension directory, and
this avoids that. Reading the JS code doesn't seem that much harder: only quotes
get damaged, and there aren't many of those in this test.

[not at google - send to devlin, 2013/08/27 19:39:53]

I do wish there was a better pattern for this.

Perhaps if we had links to the various file of importance that would help, would
allow easier source code navigation (e.g. gf in vim).

+      "        {css: [\"input[type='password']\"]});\n"
+      "    chrome.test.assertEq(['input[type=\"password\"]'], psm.css);\n"
+      "    chrome.test.succeed();\n"
+      "  },\n"
+      "\n"
+      "  function throwsOnBadCss() {\n"
+      "    function NewPageStateMatcher(obj) {\n"
+      "      return new PageStateMatcher(obj);\n"
+      "    }"
+      "    chrome.test.assertThrows(NewPageStateMatcher,\n"
+      "                             undefined,\n"
+      "                             [{css: [\"input''\"]}],\n"
+      "                             \"Invalid selector: input''\");\n"
+      "    chrome.test.succeed();\n"
+      "  },\n"
+      // TODO(jyasskin): Let the extension developer know if their
+      // selector list includes a complex selector
+      // (http://dev.w3.org/csswg/selectors4/#structure), since those
+      // are disallowed by WebDocument::watchSelectors().
+      //
+      // "  function throwsOnComplexSelector() {\n"
+      // "    function NewPageStateMatcher(obj) {\n"
+      // "      return new PageStateMatcher(obj);\n"
+      // "    }"
+      // "    chrome.test.assertThrows(NewPageStateMatcher,\n"
+      // "                             undefined,\n"
+      // "                             [{css: [\"div input\"]}],\n"
+      // "                             'compound selector');\n"
+      // "    chrome.test.succeed();\n"
+      // "  },\n"
+      "]);\n"
+      "\n");
+  ResultCatcher catcher;
+  ASSERT_TRUE(LoadExtension(ext_dir_.unpacked_path()));
+  ASSERT_TRUE(catcher.GetNextResult()) << catcher.message();
+}
+
 }  // namespace
 }  // namespace extensions