Add stub functions for chrome.* APIs in content scripts.

Most of the extensions API is not supported in content scripts for security 
purposes. Instead the typical pattern is to use messaging between content 
scripts and a background page which executes them on behalf of the script.
This is not immediately obvious to many extension developers, so this
change adds an error message to help them better understand what's going on.


BUG=26128
TEST=Try writing a content script that uses some of the extensions API stuff 
in chrome.tabs, chrome.windows, etc. You should see errors in the console 
telling you that it isn't supported in content scripts.


Review URL: http://codereview.chromium.org/366024

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@31958 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 177 insertions, 0 deletions

diff --git a/chrome/test/data/extensions/api_test/stubs/background.html b/chrome/test/data/extensions/api_test/stubs/background.html
new file mode 100644
index 0000000..b32d520
--- /dev/null
+++ b/chrome/test/data/extensions/api_test/stubs/background.html
@@ -0,0 +1,16 @@
+<script>
+
+chrome.extension.onRequest.addListener(function(msg, sender, responseFunc) {
+  if (msg == "getApi") {
+    responseFunc(JSON.parse(chrome.test.getApiDefinitions()));
+  } else if (msg == "pass") {
+    chrome.test.notifyPass();
+  } else {
+    chrome.test.notifyFail("failed");
+  }
+});
+
+// On first install, send a success message so the test can continue.
+chrome.test.notifyPass();
+
+</script>
diff --git a/chrome/test/data/extensions/api_test/stubs/content_script.js b/chrome/test/data/extensions/api_test/stubs/content_script.js
new file mode 100644
index 0000000..0f9ec84
--- /dev/null
+++ b/chrome/test/data/extensions/api_test/stubs/content_script.js
@@ -0,0 +1,150 @@
+
+// We ask the background page to get the extension API to test against. When it
+// responds we start the test.
+console.log("asking for api ...");
+chrome.extension.sendRequest("getApi", function(apis) {
+  console.log("got api response");
+  var privilegedPaths = [];
+  var unprivilegedPaths = [];
+  apis.forEach(function(module) {
+    var namespace = module.namespace;
+    if (!module.unprivileged) {
+      privilegedPaths.push(namespace);
+      return;
+    }
+
+    ["functions", "events"].forEach(function(section) {
+      if (typeof(module[section]) == "undefined")
+        return;
+       module[section].forEach(function(entry) {
+        var path = namespace + "." + entry.name;
+        if (entry.unprivileged) {
+          unprivilegedPaths.push(path);
+        } else {
+          privilegedPaths.push(path);
+        }
+      });
+    });
+
+    if (module.properties) {
+      for (var propName in module.properties) {
+        var path = namespace + "." + propName;
+        if (module.properties[propName].unprivileged) {
+          unprivilegedPaths.push(path);
+        } else {
+          privilegedPaths.push(path);
+        }
+      }
+    }
+  });
+  doTest(privilegedPaths, unprivilegedPaths);
+});
+
+
+// Tests whether missing properties of the chrome object correctly throw an
+// error on access. The path is a namespace or function/property/event etc.
+// within a namespace, and is dot-separated.
+function testPath(path, expectError) {
+  console.log("trying " + path);
+  var parts = path.split('.');
+
+  // Iterate over each component of the path, making sure all but the last part
+  // is defined. The last part should either be defined or throw an error on
+  // attempted access.
+  var module = chrome;
+  for (var i = 0; i < parts.length; i++) {
+    if (i < parts.length - 1) {
+      // Not the last component, so expect non-null / no exception.
+      try {
+        module = module[parts[i]];
+      } catch (err) {
+        console.log("testPath failed on subcomponent of " + path);
+        return false;
+      }
+    } else {
+      // This is the last component - we expect it to either be defined or
+      // to throw an error on access.
+      try {
+        if (typeof(module[parts[i]]) == "undefined") {
+          console.log(" fail (undefined and not throwing error): " +
+                      path);
+          return false;
+        } else if (!expectError) {
+          console.log(" ok (defined): " + path);
+          return true;
+        }
+      } catch (err) {
+        if (!expectError) {
+          console.log(" fail (did not expect error): " + path);
+          return false;
+        }
+        var str = err.toString();
+        if (str.search("is not supported in content scripts") != -1) {
+          console.log(" ok (correct error thrown): " + path);
+          return true;
+        } else {
+          console.log(" fail (wrong error: '" + str + "')");
+          return false;
+        }
+      }
+    }
+  }
+  console.log(" fail (no error when we were expecting one): " + path);
+  return false;
+}
+
+function displayResult(status) {
+  var div = document.createElement("div");
+  div.innerHTML = "<h1>" + status + "</h2>";
+  document.body.appendChild(div);
+}
+
+function reportSuccess() {
+  displayResult("pass");
+  chrome.extension.sendRequest("pass");
+}
+
+function reportFailure() {
+  displayResult("fail");
+  // Let the "fail" show for a little while so you can see it when running
+  // browser_tests in the debugger.
+  setTimeout(function() {
+    chrome.extension.sendRequest("fail");
+  }, 1000);
+}
+
+// Runs over each string path in privilegedPaths and unprivilegedPaths, testing
+// to ensure a proper error is thrown on access or the path is defined.
+function doTest(privilegedPaths, unprivilegedPaths) {
+  console.log("starting");
+
+  if (!privilegedPaths || privilegedPaths.length < 1 || !unprivilegedPaths ||
+      unprivilegedPaths.length < 1) {
+    port.postMessage("fail");
+    return;
+  }
+
+  var failures = [];
+  var success = true;
+
+  // Returns a function that will test a path and record any failures.
+  function makeTestFunction(expectError) {
+    return function(path) {
+      if (!testPath(path, expectError)) {
+        success = false;
+        failures.push(path);
+      }
+    };
+  }
+  privilegedPaths.forEach(makeTestFunction(true));
+  unprivilegedPaths.forEach(makeTestFunction(false));
+
+  console.log(success ? "pass" : "fail");
+  if (success) {
+    reportSuccess();
+  } else {
+    console.log("failures on:\n" + failures.join("\n"));
+    reportFailure();
+  }
+}
+
diff --git a/chrome/test/data/extensions/api_test/stubs/manifest.json b/chrome/test/data/extensions/api_test/stubs/manifest.json
new file mode 100644
index 0000000..0149ae6
--- /dev/null
+++ b/chrome/test/data/extensions/api_test/stubs/manifest.json
@@ -0,0 +1,11 @@
+{
+  "name": "Content Script Extension API Stubs Test",
+  "version": "1.0",
+  "background_page": "background.html",
+  "content_scripts": [
+    {
+      "matches": ["http://*/*", "file://*"],
+      "js":["content_script.js"]
+    }
+  ]
+}