Make ui_test_utils::ExecuteJavaScript() friendlier to use. Also, add WARN_UNUSED_RESULT to make it less likely that callers ignore failures.

BUG=57216
TEST=tests should still run

Review URL: http://codereview.chromium.org/3569005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@61119 0039d316-1c4b-4281-b951-d872f2087c98

12 files changed, 187 insertions, 169 deletions

diff --git a/chrome/browser/extensions/app_process_apitest.cc b/chrome/browser/extensions/app_process_apitest.cc
index 689a88c..deca3b0 100644
--- a/chrome/browser/extensions/app_process_apitest.cc
+++ b/chrome/browser/extensions/app_process_apitest.cc
@@ -23,13 +23,8 @@ static void WindowOpenHelper(Browser* browser,
                              RenderViewHost* opener_host,
                              const GURL& url,
                              bool newtab_process_should_equal_opener) {
-  bool result = false;
-  ui_test_utils::ExecuteJavaScriptAndExtractBool(
-      opener_host, L"",
-      L"window.open('" + UTF8ToWide(url.spec()) + L"');"
-      L"window.domAutomationController.send(true);",
-      &result);
-  ASSERT_TRUE(result);
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScript(
+      opener_host, L"", L"window.open('" + UTF8ToWide(url.spec()) + L"');"));
 
   // The above window.open call is not user-initiated, it will create
   // a popup window instead of a new tab in current window.
@@ -51,13 +46,13 @@ static void WindowOpenHelper(Browser* browser,
 // Simulates a page navigating itself to an URL, and waits for the navigation.
 static void NavigateTabHelper(TabContents* contents, const GURL& url) {
   bool result = false;
-  ui_test_utils::ExecuteJavaScriptAndExtractBool(
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractBool(
       contents->render_view_host(), L"",
       L"window.addEventListener('unload', function() {"
       L"    window.domAutomationController.send(true);"
       L"}, false);"
       L"window.location = '" + UTF8ToWide(url.spec()) + L"';",
-      &result);
+      &result));
   ASSERT_TRUE(result);
 
   if (!contents->controller().GetLastCommittedEntry() ||
diff --git a/chrome/browser/extensions/browser_action_apitest.cc b/chrome/browser/extensions/browser_action_apitest.cc
index 82f1320..67e533b 100644
--- a/chrome/browser/extensions/browser_action_apitest.cc
+++ b/chrome/browser/extensions/browser_action_apitest.cc
@@ -76,12 +76,12 @@ IN_PROC_BROWSER_TEST_F(BrowserActionApiTest, Basic) {
   // Verify the command worked.
   TabContents* tab = browser()->GetSelectedTabContents();
   bool result = false;
-  ui_test_utils::ExecuteJavaScriptAndExtractBool(
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractBool(
       tab->render_view_host(), L"",
       L"setInterval(function(){"
       L"  if(document.body.bgColor == 'red'){"
       L"    window.domAutomationController.send(true)}}, 100)",
-      &result);
+      &result));
   ASSERT_TRUE(result);
 }
 
diff --git a/chrome/browser/extensions/extension_browsertests_misc.cc b/chrome/browser/extensions/extension_browsertests_misc.cc
index 9a466bd..012420a 100644
--- a/chrome/browser/extensions/extension_browsertests_misc.cc
+++ b/chrome/browser/extensions/extension_browsertests_misc.cc
@@ -98,19 +98,19 @@ IN_PROC_BROWSER_TEST_F(ExtensionBrowserTest, OriginPrivileges) {
   ui_test_utils::NavigateToURL(
       browser(), origin_privileges_index.ReplaceComponents(make_host_a_com));
   std::string result;
-  ui_test_utils::ExecuteJavaScriptAndExtractString(
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractString(
     browser()->GetSelectedTabContents()->render_view_host(), L"",
       L"window.domAutomationController.send(document.title)",
-      &result);
+    &result));
   EXPECT_EQ(result, "Loaded");
 
   // A web host that does not have permission.
   ui_test_utils::NavigateToURL(
       browser(), origin_privileges_index.ReplaceComponents(make_host_b_com));
-  ui_test_utils::ExecuteJavaScriptAndExtractString(
-    browser()->GetSelectedTabContents()->render_view_host(), L"",
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractString(
+      browser()->GetSelectedTabContents()->render_view_host(), L"",
       L"window.domAutomationController.send(document.title)",
-      &result);
+      &result));
   EXPECT_EQ(result, "Image failed to load");
 
   // A data URL. Data URLs should always be able to load chrome-extension://
@@ -121,10 +121,10 @@ IN_PROC_BROWSER_TEST_F(ExtensionBrowserTest, OriginPrivileges) {
                     .AppendASCII("index.html"), &file_source));
   ui_test_utils::NavigateToURL(browser(),
       GURL(std::string("data:text/html;charset=utf-8,") + file_source));
-  ui_test_utils::ExecuteJavaScriptAndExtractString(
-    browser()->GetSelectedTabContents()->render_view_host(), L"",
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractString(
+      browser()->GetSelectedTabContents()->render_view_host(), L"",
       L"window.domAutomationController.send(document.title)",
-      &result);
+      &result));
   EXPECT_EQ(result, "Loaded");
 
   // A different extension. Extensions should always be able to load each
@@ -134,10 +134,10 @@ IN_PROC_BROWSER_TEST_F(ExtensionBrowserTest, OriginPrivileges) {
   ui_test_utils::NavigateToURL(
       browser(),
       GURL("chrome-extension://pbkkcbgdkliohhfaeefcijaghglkahja/index.html"));
-  ui_test_utils::ExecuteJavaScriptAndExtractString(
-    browser()->GetSelectedTabContents()->render_view_host(), L"",
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractString(
+      browser()->GetSelectedTabContents()->render_view_host(), L"",
       L"window.domAutomationController.send(document.title)",
-      &result);
+      &result));
   EXPECT_EQ(result, "Loaded");
 }
 
@@ -154,9 +154,9 @@ IN_PROC_BROWSER_TEST_F(ExtensionBrowserTest, TabContents) {
       GURL("chrome-extension://behllobkkfkfnphdnhnkndlbkcpglgmj/page.html"));
 
   bool result = false;
-  ui_test_utils::ExecuteJavaScriptAndExtractBool(
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractBool(
       browser()->GetSelectedTabContents()->render_view_host(), L"",
-      L"testTabsAPI()", &result);
+      L"testTabsAPI()", &result));
   EXPECT_TRUE(result);
 
   // There was a bug where we would crash if we navigated to a page in the same
@@ -166,9 +166,9 @@ IN_PROC_BROWSER_TEST_F(ExtensionBrowserTest, TabContents) {
       browser(),
       GURL("chrome-extension://behllobkkfkfnphdnhnkndlbkcpglgmj/page.html"));
   result = false;
-  ui_test_utils::ExecuteJavaScriptAndExtractBool(
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractBool(
       browser()->GetSelectedTabContents()->render_view_host(), L"",
-      L"testTabsAPI()", &result);
+      L"testTabsAPI()", &result));
   EXPECT_TRUE(result);
 }
 
@@ -610,22 +610,20 @@ IN_PROC_BROWSER_TEST_F(ExtensionBrowserTest, LastError) {
   ExtensionHost* host = FindHostWithPath(manager, "/bg.html", 1);
 
   bool result = false;
-  ui_test_utils::ExecuteJavaScriptAndExtractBool(
-      host->render_view_host(), L"", L"testLastError()", &result);
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractBool(
+      host->render_view_host(), L"", L"testLastError()", &result));
   EXPECT_TRUE(result);
 }
 
 // Helper function for common code shared by the 3 WindowOpen tests below.
-static TabContents* WindowOpenHelper(Browser* browser, const GURL& start_url,
-                                    const std::string& newtab_url) {
+static void WindowOpenHelper(Browser* browser, const GURL& start_url,
+                             const std::string& newtab_url,
+                             TabContents** newtab_result) {
   ui_test_utils::NavigateToURL(browser, start_url);
 
-  bool result = false;
-  ui_test_utils::ExecuteJavaScriptAndExtractBool(
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScript(
       browser->GetSelectedTabContents()->render_view_host(), L"",
-      L"window.open('" + UTF8ToWide(newtab_url) + L"');"
-      L"window.domAutomationController.send(true);", &result);
-  EXPECT_TRUE(result);
+      L"window.open('" + UTF8ToWide(newtab_url) + L"');"));
 
   // Now the active tab in last active window should be the new tab.
   Browser* last_active_browser = BrowserList::GetLastActive();
@@ -636,9 +634,10 @@ static TabContents* WindowOpenHelper(Browser* browser, const GURL& start_url,
   if (!newtab->controller().GetLastCommittedEntry() ||
       newtab->controller().GetLastCommittedEntry()->url() != expected_url)
     ui_test_utils::WaitForNavigation(&newtab->controller());
-  EXPECT_EQ(expected_url, newtab->controller().GetLastCommittedEntry()->url());
-
-  return newtab;
+  EXPECT_EQ(expected_url,
+            newtab->controller().GetLastCommittedEntry()->url());
+  if (newtab_result)
+    *newtab_result = newtab;
 }
 
 // Tests that an extension page can call window.open to an extension URL and
@@ -647,15 +646,16 @@ IN_PROC_BROWSER_TEST_F(ExtensionBrowserTest, WindowOpenExtension) {
   ASSERT_TRUE(LoadExtension(
       test_data_dir_.AppendASCII("uitest").AppendASCII("window_open")));
 
-  TabContents* newtab = WindowOpenHelper(
+  TabContents* newtab;
+  ASSERT_NO_FATAL_FAILURE(WindowOpenHelper(
       browser(),
       GURL(std::string("chrome-extension://") + last_loaded_extension_id_ +
            "/test.html"),
-      "newtab.html");
+      "newtab.html", &newtab));
 
   bool result = false;
-  ui_test_utils::ExecuteJavaScriptAndExtractBool(
-      newtab->render_view_host(), L"", L"testExtensionApi()", &result);
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractBool(
+      newtab->render_view_host(), L"", L"testExtensionApi()", &result));
   EXPECT_TRUE(result);
 }
 
@@ -665,11 +665,11 @@ IN_PROC_BROWSER_TEST_F(ExtensionBrowserTest, WindowOpenInvalidExtension) {
   ASSERT_TRUE(LoadExtension(
       test_data_dir_.AppendASCII("uitest").AppendASCII("window_open")));
 
-  WindowOpenHelper(
+  ASSERT_NO_FATAL_FAILURE(WindowOpenHelper(
       browser(),
       GURL(std::string("chrome-extension://") + last_loaded_extension_id_ +
            "/test.html"),
-      "chrome-extension://thisissurelynotavalidextensionid/newtab.html");
+      "chrome-extension://thisissurelynotavalidextensionid/newtab.html", NULL));
 
   // If we got to this point, we didn't crash, so we're good.
 }
@@ -682,16 +682,18 @@ IN_PROC_BROWSER_TEST_F(ExtensionBrowserTest, WindowOpenNoPrivileges) {
   ASSERT_TRUE(LoadExtension(
       test_data_dir_.AppendASCII("uitest").AppendASCII("window_open")));
 
-  TabContents* newtab = WindowOpenHelper(
+  TabContents* newtab;
+  ASSERT_NO_FATAL_FAILURE(WindowOpenHelper(
       browser(),
       GURL("about:blank"),
       std::string("chrome-extension://") + last_loaded_extension_id_ +
-          "/newtab.html");
+          "/newtab.html",
+      &newtab));
 
   // Extension API should succeed.
   bool result = false;
-  ui_test_utils::ExecuteJavaScriptAndExtractBool(
-      newtab->render_view_host(), L"", L"testExtensionApi()", &result);
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractBool(
+      newtab->render_view_host(), L"", L"testExtensionApi()", &result));
   EXPECT_TRUE(result);
 }
 
@@ -717,8 +719,8 @@ IN_PROC_BROWSER_TEST_F(ExtensionBrowserTest, MAYBE_PluginLoadUnload) {
 
   // With no extensions, the plugin should not be loaded.
   bool result = false;
-  ui_test_utils::ExecuteJavaScriptAndExtractBool(
-      tab->render_view_host(), L"", L"testPluginWorks()", &result);
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractBool(
+      tab->render_view_host(), L"", L"testPluginWorks()", &result));
   EXPECT_FALSE(result);
 
   ExtensionsService* service = browser()->profile()->GetExtensionsService();
@@ -727,13 +729,13 @@ IN_PROC_BROWSER_TEST_F(ExtensionBrowserTest, MAYBE_PluginLoadUnload) {
   EXPECT_EQ(size_before + 1, service->extensions()->size());
   // Now the plugin should be in the cache, but we have to reload the page for
   // it to work.
-  ui_test_utils::ExecuteJavaScriptAndExtractBool(
-      tab->render_view_host(), L"", L"testPluginWorks()", &result);
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractBool(
+      tab->render_view_host(), L"", L"testPluginWorks()", &result));
   EXPECT_FALSE(result);
   browser()->Reload(CURRENT_TAB);
   ui_test_utils::WaitForNavigationInCurrentTab(browser());
-  ui_test_utils::ExecuteJavaScriptAndExtractBool(
-      tab->render_view_host(), L"", L"testPluginWorks()", &result);
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractBool(
+      tab->render_view_host(), L"", L"testPluginWorks()", &result));
   EXPECT_TRUE(result);
 
   EXPECT_EQ(size_before + 1, service->extensions()->size());
@@ -742,8 +744,8 @@ IN_PROC_BROWSER_TEST_F(ExtensionBrowserTest, MAYBE_PluginLoadUnload) {
 
   // Now the plugin should be unloaded, and the page should be broken.
 
-  ui_test_utils::ExecuteJavaScriptAndExtractBool(
-      tab->render_view_host(), L"", L"testPluginWorks()", &result);
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractBool(
+      tab->render_view_host(), L"", L"testPluginWorks()", &result));
   EXPECT_FALSE(result);
 
   // If we reload the extension and page, it should work again.
@@ -752,8 +754,8 @@ IN_PROC_BROWSER_TEST_F(ExtensionBrowserTest, MAYBE_PluginLoadUnload) {
   EXPECT_EQ(size_before + 1, service->extensions()->size());
   browser()->Reload(CURRENT_TAB);
   ui_test_utils::WaitForNavigationInCurrentTab(browser());
-  ui_test_utils::ExecuteJavaScriptAndExtractBool(
-      tab->render_view_host(), L"", L"testPluginWorks()", &result);
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractBool(
+      tab->render_view_host(), L"", L"testPluginWorks()", &result));
   EXPECT_TRUE(result);
 }
 
@@ -764,7 +766,6 @@ static const wchar_t* jscript_click_option_button =
     L"      document, null, XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE,"
     L"      null).snapshotItem(0);"
     L"  button.click();"
-    L"  window.domAutomationController.send(0);"
     L"})();";
 
 // Test that an extension with an options page makes an 'Options' button appear
@@ -782,9 +783,9 @@ IN_PROC_BROWSER_TEST_F(ExtensionBrowserTest, DISABLED_OptionsPage) {
   // Go to the chrome://extensions page and click the Options button.
   ui_test_utils::NavigateToURL(browser(), GURL(chrome::kChromeUIExtensionsURL));
   TabStripModel* tab_strip = browser()->tabstrip_model();
-  TabContents* extensions_tab = browser()->GetSelectedTabContents();
-  ui_test_utils::ExecuteJavaScript(extensions_tab->render_view_host(), L"",
-                                   jscript_click_option_button);
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScript(
+      browser()->GetSelectedTabContents()->render_view_host(), L"",
+      jscript_click_option_button));
 
   // If the options page hasn't already come up, wait for it.
   if (tab_strip->count() == 1) {
@@ -849,8 +850,7 @@ IN_PROC_BROWSER_TEST_F(ExtensionBrowserTest, PropertyAppIsInstalled) {
 
   // Test that trying to set window.chrome.app.isInstalled throws
   // an exception.
-  ASSERT_TRUE(
-      ui_test_utils::ExecuteJavaScriptAndExtractString(
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractString(
           browser()->GetSelectedTabContents()->render_view_host(),
           L"",
           L"window.domAutomationController.send("
diff --git a/chrome/browser/extensions/extension_devtools_browsertests.cc b/chrome/browser/extensions/extension_devtools_browsertests.cc
index 4afcb3c..c195aa7 100644
--- a/chrome/browser/extensions/extension_devtools_browsertests.cc
+++ b/chrome/browser/extensions/extension_devtools_browsertests.cc
@@ -69,8 +69,8 @@ IN_PROC_BROWSER_TEST_F(ExtensionDevToolsBrowserTest, FLAKY_TimelineApi) {
   bool result = false;
   std::wstring register_listeners_js = base::StringPrintf(
       L"setListenersOnTab(%d)", tab_id);
-  ui_test_utils::ExecuteJavaScriptAndExtractBool(
-      host->render_view_host(), L"", register_listeners_js, &result);
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractBool(
+      host->render_view_host(), L"", register_listeners_js, &result));
   EXPECT_TRUE(result);
 
   // Setting the events should have caused an ExtensionDevToolsBridge to be
@@ -85,16 +85,16 @@ IN_PROC_BROWSER_TEST_F(ExtensionDevToolsBrowserTest, FLAKY_TimelineApi) {
 
   DevToolsClientMsg_DispatchToAPU pageEventMessage("");
   devtools_client_host->SendMessageToClient(pageEventMessage);
-  ui_test_utils::ExecuteJavaScriptAndExtractBool(
-      host->render_view_host(), L"", L"testReceivePageEvent()", &result);
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractBool(
+      host->render_view_host(), L"", L"testReceivePageEvent()", &result));
   EXPECT_TRUE(result);
 
   // Test onTabClose event.
   result = false;
   devtools_manager->UnregisterDevToolsClientHostFor(
       tab_contents->render_view_host());
-  ui_test_utils::ExecuteJavaScriptAndExtractBool(
-      host->render_view_host(), L"", L"testReceiveTabCloseEvent()", &result);
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractBool(
+      host->render_view_host(), L"", L"testReceiveTabCloseEvent()", &result));
   EXPECT_TRUE(result);
 }
 
@@ -125,8 +125,8 @@ IN_PROC_BROWSER_TEST_F(ExtensionDevToolsBrowserTest, ProcessRefCounting) {
   bool result = false;
   std::wstring register_listeners_js = base::StringPrintf(
       L"setListenersOnTab(%d)", tab_id);
-  ui_test_utils::ExecuteJavaScriptAndExtractBool(
-      host_one->render_view_host(), L"", register_listeners_js, &result);
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractBool(
+      host_one->render_view_host(), L"", register_listeners_js, &result));
   EXPECT_TRUE(result);
 
   // Setting the event listeners should have caused an ExtensionDevToolsBridge
@@ -137,15 +137,15 @@ IN_PROC_BROWSER_TEST_F(ExtensionDevToolsBrowserTest, ProcessRefCounting) {
   // Register listeners from the second extension as well.
   std::wstring script = base::StringPrintf(L"registerListenersForTab(%d)",
                                            tab_id);
-  ui_test_utils::ExecuteJavaScriptAndExtractBool(
-      host_two->render_view_host(), L"", script, &result);
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractBool(
+      host_two->render_view_host(), L"", script, &result));
   EXPECT_TRUE(result);
 
   // Removing the listeners from the first extension should leave the bridge
   // alive.
   result = false;
-  ui_test_utils::ExecuteJavaScriptAndExtractBool(
-      host_one->render_view_host(), L"", L"unregisterListeners()", &result);
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractBool(
+      host_one->render_view_host(), L"", L"unregisterListeners()", &result));
   EXPECT_TRUE(result);
   ASSERT_TRUE(devtools_manager->GetDevToolsClientHostFor(
       tab_contents->render_view_host()));
@@ -153,8 +153,8 @@ IN_PROC_BROWSER_TEST_F(ExtensionDevToolsBrowserTest, ProcessRefCounting) {
   // Removing the listeners from the second extension should tear the bridge
   // down.
   result = false;
-  ui_test_utils::ExecuteJavaScriptAndExtractBool(
-      host_two->render_view_host(), L"", L"unregisterListeners()", &result);
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractBool(
+      host_two->render_view_host(), L"", L"unregisterListeners()", &result));
   EXPECT_TRUE(result);
   ASSERT_FALSE(devtools_manager->GetDevToolsClientHostFor(
       tab_contents->render_view_host()));
diff --git a/chrome/browser/extensions/extension_incognito_apitest.cc b/chrome/browser/extensions/extension_incognito_apitest.cc
index c287fda..cd29ab8 100644
--- a/chrome/browser/extensions/extension_incognito_apitest.cc
+++ b/chrome/browser/extensions/extension_incognito_apitest.cc
@@ -35,10 +35,10 @@ IN_PROC_BROWSER_TEST_F(ExtensionBrowserTest, IncognitoNoScript) {
 
   // Verify the script didn't run.
   bool result = false;
-  ui_test_utils::ExecuteJavaScriptAndExtractBool(
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractBool(
       tab->render_view_host(), L"",
       L"window.domAutomationController.send(document.title == 'Unmodified')",
-      &result);
+      &result));
   EXPECT_TRUE(result);
 }
 
@@ -71,10 +71,10 @@ IN_PROC_BROWSER_TEST_F(ExtensionBrowserTest, IncognitoYesScript) {
 
   // Verify the script ran.
   bool result = false;
-  ui_test_utils::ExecuteJavaScriptAndExtractBool(
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractBool(
       tab->render_view_host(), L"",
       L"window.domAutomationController.send(document.title == 'modified')",
-      &result);
+      &result));
   EXPECT_TRUE(result);
 }
 
diff --git a/chrome/browser/extensions/extension_startup_browsertest.cc b/chrome/browser/extensions/extension_startup_browsertest.cc
index 5342bc1..3f961f7 100644
--- a/chrome/browser/extensions/extension_startup_browsertest.cc
+++ b/chrome/browser/extensions/extension_startup_browsertest.cc
@@ -116,19 +116,19 @@ class ExtensionStartupTestBase : public InProcessBrowserTest {
     ui_test_utils::NavigateToURL(browser(), net::FilePathToFileURL(test_file));
 
     bool result = false;
-    ui_test_utils::ExecuteJavaScriptAndExtractBool(
+    ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractBool(
         browser()->GetSelectedTabContents()->render_view_host(), L"",
         L"window.domAutomationController.send("
         L"document.defaultView.getComputedStyle(document.body, null)."
         L"getPropertyValue('background-color') == 'rgb(245, 245, 220)')",
-        &result);
+        &result));
     EXPECT_EQ(expect_css, result);
 
     result = false;
-    ui_test_utils::ExecuteJavaScriptAndExtractBool(
+    ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractBool(
         browser()->GetSelectedTabContents()->render_view_host(), L"",
         L"window.domAutomationController.send(document.title == 'Modified')",
-        &result);
+        &result));
     EXPECT_EQ(expect_script, result);
   }
 
diff --git a/chrome/browser/find_bar_host_browsertest.cc b/chrome/browser/find_bar_host_browsertest.cc
index 11c5f3e..22a1c26 100644
--- a/chrome/browser/find_bar_host_browsertest.cc
+++ b/chrome/browser/find_bar_host_browsertest.cc
@@ -195,14 +195,16 @@ IN_PROC_BROWSER_TEST_F(FindInPageControllerTest, FindInPageFrames) {
   EXPECT_EQ(0, ordinal);
 }
 
-std::string FocusedOnPage(TabContents* tab_contents) {
-  std::string result;
-  ui_test_utils::ExecuteJavaScriptAndExtractString(
+// Specifying a prototype so that we can add the WARN_UNUSED_RESULT attribute.
+bool FocusedOnPage(TabContents* tab_contents, std::string* result)
+    WARN_UNUSED_RESULT;
+
+bool FocusedOnPage(TabContents* tab_contents, std::string* result) {
+  return ui_test_utils::ExecuteJavaScriptAndExtractString(
       tab_contents->render_view_host(),
       L"",
       L"window.domAutomationController.send(getFocusedElement());",
-      &result);
-  return result;
+      result);
 }
 
 // This tests the FindInPage end-state, in other words: what is focused when you
@@ -219,7 +221,9 @@ IN_PROC_BROWSER_TEST_F(FindInPageControllerTest, FindInPageEndState) {
   ASSERT_TRUE(NULL != tab_contents);
 
   // Verify that nothing has focus.
-  ASSERT_STREQ("{nothing focused}", FocusedOnPage(tab_contents).c_str());
+  std::string result;
+  ASSERT_TRUE(FocusedOnPage(tab_contents, &result));
+  ASSERT_STREQ("{nothing focused}", result.c_str());
 
   // Search for a text that exists within a link on the page.
   int ordinal = 0;
@@ -231,7 +235,8 @@ IN_PROC_BROWSER_TEST_F(FindInPageControllerTest, FindInPageEndState) {
   tab_contents->StopFinding(FindBarController::kKeepSelection);
 
   // Verify that the link is focused.
-  EXPECT_STREQ("link1", FocusedOnPage(tab_contents).c_str());
+  ASSERT_TRUE(FocusedOnPage(tab_contents, &result));
+  EXPECT_STREQ("link1", result.c_str());
 
   // Search for a text that exists within a link on the page.
   EXPECT_EQ(1, FindInPageWchar(tab_contents, L"Google",
@@ -239,18 +244,18 @@ IN_PROC_BROWSER_TEST_F(FindInPageControllerTest, FindInPageEndState) {
   EXPECT_EQ(1, ordinal);
 
   // Move the selection to link 1, after searching.
-  std::string result;
-  ui_test_utils::ExecuteJavaScriptAndExtractString(
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractString(
       tab_contents->render_view_host(),
       L"",
       L"window.domAutomationController.send(selectLink1());",
-      &result);
+      &result));
 
   // End the find session.
   tab_contents->StopFinding(FindBarController::kKeepSelection);
 
   // Verify that link2 is not focused.
-  EXPECT_STREQ("", FocusedOnPage(tab_contents).c_str());
+  ASSERT_TRUE(FocusedOnPage(tab_contents, &result));
+  EXPECT_STREQ("", result.c_str());
 }
 
 // This test loads a single-frame page and makes sure the ordinal returned makes
@@ -314,11 +319,11 @@ IN_PROC_BROWSER_TEST_F(FindInPageControllerTest,
 
   // Move the selection to link 1, after searching.
   std::string result;
-  ui_test_utils::ExecuteJavaScriptAndExtractString(
+  ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractString(
       tab_contents->render_view_host(),
       L"",
       L"window.domAutomationController.send(selectLink1());",
-      &result);
+      &result));
 
   // Do a find-next after the selection.  This should move forward
   // from there to the 3rd instance of 'google'.
diff --git a/chrome/browser/geolocation/geolocation_browsertest.cc b/chrome/browser/geolocation/geolocation_browsertest.cc
index 382b614..6617f90 100644
--- a/chrome/browser/geolocation/geolocation_browsertest.cc
+++ b/chrome/browser/geolocation/geolocation_browsertest.cc
@@ -62,9 +62,9 @@ class IFrameLoader : public NotificationObserver {
     script = StringPrintf(
         "window.domAutomationController.send(getIFrameSrc(%d))", iframe_id);
     std::string iframe_src;
-    ui_test_utils::ExecuteJavaScriptAndExtractString(
+    EXPECT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractString(
         browser->GetSelectedTabContents()->render_view_host(),
-        L"", UTF8ToWide(script), &iframe_src);
+        L"", UTF8ToWide(script), &iframe_src));
     iframe_url_ = GURL(iframe_src);
   }
 
@@ -321,9 +321,9 @@ class GeolocationBrowserTest : public InProcessBrowserTest {
     std::string script = StringPrintf(
         "window.domAutomationController.send(%s)", function.c_str());
     std::string result;
-    ui_test_utils::ExecuteJavaScriptAndExtractString(
+    ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractString(
         tab_contents->render_view_host(),
-        iframe_xpath_, UTF8ToWide(script), &result);
+        iframe_xpath_, UTF8ToWide(script), &result));
     EXPECT_EQ(expected, result);
   }
 
diff --git a/chrome/browser/in_process_webkit/indexed_db_browsertest.cc b/chrome/browser/in_process_webkit/indexed_db_browsertest.cc
index 15f004e..5ea451a 100644
--- a/chrome/browser/in_process_webkit/indexed_db_browsertest.cc
+++ b/chrome/browser/in_process_webkit/indexed_db_browsertest.cc
@@ -67,15 +67,6 @@ class IndexedDBBrowserTest : public InProcessBrowserTest {
     return ui_test_utils::GetTestUrl(kTestDir, file_path);
   }
 
-  std::string GetTestLog() {
-    std::string script = "window.domAutomationController.send(getLog())";
-    std::string js_result;
-    ui_test_utils::ExecuteJavaScriptAndExtractString(
-        browser()->GetSelectedTabContents()->render_view_host(),
-        L"", UTF8ToWide(script), &js_result);
-    return js_result;
-  }
-
   void SimpleTest(const GURL& test_url) {
     // The test page will open a cursor on IndexedDB, then navigate to either a
     // #pass or #fail ref.
@@ -83,7 +74,10 @@ class IndexedDBBrowserTest : public InProcessBrowserTest {
         browser(), test_url, 2);
     std::string result = browser()->GetSelectedTabContents()->GetURL().ref();
     if (result != "pass") {
-      std::string js_result = GetTestLog();
+      std::string js_result;
+      ASSERT_TRUE(ui_test_utils::ExecuteJavaScriptAndExtractString(
+          browser()->GetSelectedTabContents()->render_view_host(), L"",
+          L"window.domAutomationController.send(getLog())", &js_result));
       FAIL() << "Failed: " << js_result;
     }
   }
diff --git a/chrome/renderer/automation/dom_automation_controller.cc b/chrome/renderer/automation/dom_automation_controller.cc
index 6c3e8a5..8d708d1 100644
--- a/chrome/renderer/automation/dom_automation_controller.cc
+++ b/chrome/renderer/automation/dom_automation_controller.cc
@@ -72,19 +72,17 @@ void DomAutomationController::Send(const CppArgumentList& args,
     }
   }
 
-  bool succeeded = serializer.Serialize(*value);
-  if (!succeeded) {
+  if (!serializer.Serialize(*value)) {
     result->SetNull();
     return;
   }
 
-  succeeded = sender_->Send(
-    new ViewHostMsg_DomOperationResponse(routing_id_, json, automation_id_));
+  bool succeeded = sender_->Send(
+      new ViewHostMsg_DomOperationResponse(routing_id_, json, automation_id_));
+  result->Set(succeeded);
 
   automation_id_ = MSG_ROUTING_NONE;
 
-  result->Set(succeeded);
-  return;
 }
 
 void DomAutomationController::SendJSON(const CppArgumentList& args,
diff --git a/chrome/test/ui_test_utils.cc b/chrome/test/ui_test_utils.cc
index 964ae60..f570707 100644
--- a/chrome/test/ui_test_utils.cc
+++ b/chrome/test/ui_test_utils.cc
@@ -109,13 +109,11 @@ class DOMOperationObserver : public NotificationObserver {
     MessageLoopForUI::current()->Quit();
   }
 
-  bool GetResponse(std::string* response) {
+  bool GetResponse(std::string* response) WARN_UNUSED_RESULT {
     *response = response_;
     return did_respond_;
   }
 
-  std::string response() const { return response_; }
-
  private:
   NotificationRegistrar registrar_;
   std::string response_;
@@ -277,18 +275,18 @@ class InProcessJavaScriptExecutionController
 
  protected:
   // Executes |script| and sets the JSON response |json|.
-  bool ExecuteJavaScriptAndGetJSON(const std::string& script,
-                                   std::string* json) {
+  virtual bool ExecuteJavaScriptAndGetJSON(const std::string& script,
+                                           std::string* json) {
     render_view_host_->ExecuteJavascriptInWebFrame(L"", UTF8ToWide(script));
     DOMOperationObserver dom_op_observer(render_view_host_);
     return dom_op_observer.GetResponse(json);
   }
 
-  void FirstObjectAdded() {
+  virtual void FirstObjectAdded() {
     AddRef();
   }
 
-  void LastObjectRemoved() {
+  virtual void LastObjectRemoved() {
     Release();
   }
 
@@ -297,6 +295,52 @@ class InProcessJavaScriptExecutionController
   RenderViewHost* render_view_host_;
 };
 
+// Specifying a prototype so that we can add the WARN_UNUSED_RESULT attribute.
+bool ExecuteJavaScriptHelper(RenderViewHost* render_view_host,
+                             const std::wstring& frame_xpath,
+                             const std::wstring& original_script,
+                             scoped_ptr<Value>* result) WARN_UNUSED_RESULT;
+
+// Executes the passed |original_script| in the frame pointed to by
+// |frame_xpath|.  If |result| is not NULL, stores the value that the evaluation
+// of the script in |result|.  Returns true on success.
+bool ExecuteJavaScriptHelper(RenderViewHost* render_view_host,
+                             const std::wstring& frame_xpath,
+                             const std::wstring& original_script,
+                             scoped_ptr<Value>* result) {
+  // TODO(jcampan): we should make the domAutomationController not require an
+  //                automation id.
+  std::wstring script = L"window.domAutomationController.setAutomationId(0);" +
+      original_script;
+  render_view_host->ExecuteJavascriptInWebFrame(frame_xpath, script);
+  DOMOperationObserver dom_op_observer(render_view_host);
+  std::string json;
+  if (!dom_op_observer.GetResponse(&json))
+    return false;
+
+  // Nothing more to do for callers that ignore the returned JS value.
+  if (!result)
+    return true;
+
+  // Wrap |json| in an array before deserializing because valid JSON has an
+  // array or an object as the root.
+  json.insert(0, "[");
+  json.append("]");
+
+  scoped_ptr<Value> root_val(base::JSONReader::Read(json, true));
+  if (!root_val->IsType(Value::TYPE_LIST))
+    return false;
+
+  ListValue* list = static_cast<ListValue*>(root_val.get());
+  Value* result_val;
+  if (!list || !list->GetSize() ||
+      !list->Remove(0, &result_val))  // Remove gives us ownership of the value.
+    return false;
+
+  result->reset(result_val);
+  return true;
+}
+
 }  // namespace
 
 void RunMessageLoop() {
@@ -410,32 +454,12 @@ DOMElementProxyRef GetActiveDOMDocument(Browser* browser) {
   return executor->GetObjectProxy<DOMElementProxy>(element_handle);
 }
 
-Value* ExecuteJavaScript(RenderViewHost* render_view_host,
-                         const std::wstring& frame_xpath,
-                         const std::wstring& original_script) {
-  // TODO(jcampan): we should make the domAutomationController not require an
-  //                automation id.
-  std::wstring script = L"window.domAutomationController.setAutomationId(0);" +
-      original_script;
-  render_view_host->ExecuteJavascriptInWebFrame(frame_xpath, script);
-  DOMOperationObserver dom_op_observer(render_view_host);
-  std::string json = dom_op_observer.response();
-  // Wrap |json| in an array before deserializing because valid JSON has an
-  // array or an object as the root.
-  json.insert(0, "[");
-  json.append("]");
-
-  scoped_ptr<Value> root_val(base::JSONReader::Read(json, true));
-  if (!root_val->IsType(Value::TYPE_LIST))
-    return NULL;
-
-  ListValue* list = static_cast<ListValue*>(root_val.get());
-  Value* result;
-  if (!list || !list->GetSize() ||
-      !list->Remove(0, &result))  // Remove gives us ownership of the value.
-    return NULL;
-
-  return result;
+bool ExecuteJavaScript(RenderViewHost* render_view_host,
+                       const std::wstring& frame_xpath,
+                       const std::wstring& original_script) {
+  std::wstring script =
+      original_script + L"window.domAutomationController.send(0);";
+  return ExecuteJavaScriptHelper(render_view_host, frame_xpath, script, NULL);
 }
 
 bool ExecuteJavaScriptAndExtractInt(RenderViewHost* render_view_host,
@@ -443,9 +467,9 @@ bool ExecuteJavaScriptAndExtractInt(RenderViewHost* render_view_host,
                                     const std::wstring& script,
                                     int* result) {
   DCHECK(result);
-  scoped_ptr<Value> value(ExecuteJavaScript(render_view_host, frame_xpath,
-                                            script));
-  if (!value.get())
+  scoped_ptr<Value> value;
+  if (!ExecuteJavaScriptHelper(render_view_host, frame_xpath, script, &value) ||
+      !value.get())
     return false;
 
   return value->GetAsInteger(result);
@@ -456,9 +480,9 @@ bool ExecuteJavaScriptAndExtractBool(RenderViewHost* render_view_host,
                                      const std::wstring& script,
                                      bool* result) {
   DCHECK(result);
-  scoped_ptr<Value> value(ExecuteJavaScript(render_view_host, frame_xpath,
-                                            script));
-  if (!value.get())
+  scoped_ptr<Value> value;
+  if (!ExecuteJavaScriptHelper(render_view_host, frame_xpath, script, &value) ||
+      !value.get())
     return false;
 
   return value->GetAsBoolean(result);
@@ -469,9 +493,9 @@ bool ExecuteJavaScriptAndExtractString(RenderViewHost* render_view_host,
                                        const std::wstring& script,
                                        std::string* result) {
   DCHECK(result);
-  scoped_ptr<Value> value(ExecuteJavaScript(render_view_host, frame_xpath,
-                                            script));
-  if (!value.get())
+  scoped_ptr<Value> value;
+  if (!ExecuteJavaScriptHelper(render_view_host, frame_xpath, script, &value) ||
+      !value.get())
     return false;
 
   return value->GetAsString(result);
diff --git a/chrome/test/ui_test_utils.h b/chrome/test/ui_test_utils.h
index 9e6a2e1..fef6f6b5 100644
--- a/chrome/test/ui_test_utils.h
+++ b/chrome/test/ui_test_utils.h
@@ -107,11 +107,13 @@ void NavigateToURLBlockUntilNavigationsComplete(Browser* browser,
 DOMElementProxyRef GetActiveDOMDocument(Browser* browser);
 
 // Executes the passed |script| in the frame pointed to by |frame_xpath| (use
-// empty string for main frame) and returns the value the evaluation of the
-// script returned.  The caller owns the returned value.
-Value* ExecuteJavaScript(RenderViewHost* render_view_host,
-                         const std::wstring& frame_xpath,
-                         const std::wstring& script);
+// empty string for main frame).  The |script| should not invoke
+// domAutomationController.send(); otherwise, your test will hang or be flaky.
+// If you want to extract a result, use one of the below functions.
+// Returns true on success.
+bool ExecuteJavaScript(RenderViewHost* render_view_host,
+                       const std::wstring& frame_xpath,
+                       const std::wstring& script) WARN_UNUSED_RESULT;
 
 // The following methods executes the passed |script| in the frame pointed to by
 // |frame_xpath| (use empty string for main frame) and sets |result| to the
@@ -123,15 +125,15 @@ Value* ExecuteJavaScript(RenderViewHost* render_view_host,
 bool ExecuteJavaScriptAndExtractInt(RenderViewHost* render_view_host,
                                     const std::wstring& frame_xpath,
                                     const std::wstring& script,
-                                    int* result);
+                                    int* result) WARN_UNUSED_RESULT;
 bool ExecuteJavaScriptAndExtractBool(RenderViewHost* render_view_host,
                                      const std::wstring& frame_xpath,
                                      const std::wstring& script,
-                                     bool* result);
+                                     bool* result) WARN_UNUSED_RESULT;
 bool ExecuteJavaScriptAndExtractString(RenderViewHost* render_view_host,
                                        const std::wstring& frame_xpath,
                                        const std::wstring& script,
-                                       std::string* result);
+                                       std::string* result) WARN_UNUSED_RESULT;
 
 // Generate the file path for testing a particular test.
 // The file for the tests is all located in