Add test for accessibility histograms.

chrome/browser/accessibility/browser_accessibility_state_browsertest.cc

+// Copyright (c) 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 "content/public/browser/browser_accessibility_state.h"
+#include "chrome/test/base/in_process_browser_test.h"
+#include "chrome/test/base/uma_histogram_helper.h"
+
+namespace content {
+
+class BrowserAccessibilityStateImplTest : public InProcessBrowserTest {
+};
+
+IN_PROC_BROWSER_TEST_F(BrowserAccessibilityStateImplTest, TestHistograms) {
+  UMAHistogramHelper histograms;
+
+  BrowserAccessibilityState::GetInstance()->UpdateHistograms();
+  histograms.Fetch();
+  histograms.ExpectTotalCount("Accessibility.State", 1);
+#if defined(OS_WIN)
+  histograms.ExpectTotalCount("Accessibility.WinScreenReader", 1);
+#elif defined(OS_CHROMEOS)
+  histograms.ExpectTotalCount("Accessibility.CrosSpokenFeedback", 1);
+#endif
+}
+
+}  // namespace content