Disable built-in TTS engine during Chrome OS accessibility E2E tests

All of these tests were triggering starting the "real" TTS engine, even
though a mock TTS engine was installed.

I ran all of the ChromeVoxBackground tests before and after this change
on my system with --test-launcher-jobs=20. If the speech engine is
installed, the average test time drops 30%, from 8200 ms to 6200 ms.
Even if the speech engine is not installed, it still drops 25% from
7700 ms to 6200 ms.

Bug: none
Change-Id: Iea23951ce397176cd1fda64d801422f3031a1fba
AX-Relnotes: N/A
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2422585
Commit-Queue: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: David Tseng <dtseng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#810437}

chrome/browser/resources/chromeos/accessibility/accessibility_common/accessibility_common_test.js

@@ -14,6 +14,7 @@ AccessibilityCommonE2ETest = class extends E2ETestBase {
 
   /** @override */
   testGenCppIncludes() {
+    super.testGenCppIncludes();
     GEN(`
 #include "ash/accessibility/accessibility_delegate.h"
 #include "ash/shell.h"
@@ -27,6 +28,7 @@ AccessibilityCommonE2ETest = class extends E2ETestBase {
 
   /** @override */
   testGenPreamble() {
+    super.testGenPreamble();
     // Note that at least one accessibility common feature has to be enabled for
     // the extension to load. Extension load is required for this test suite to
     // have a place to be injected.

chrome/browser/resources/chromeos/accessibility/chromevox/testing/chromevox_e2e_test_base.js

@@ -15,6 +15,7 @@ GEN_INCLUDE([
 ChromeVoxE2ETest = class extends E2ETestBase {
   /** @override */
   testGenCppIncludes() {
+    super.testGenCppIncludes();
     GEN(`
   #include "ash/accessibility/accessibility_delegate.h"
   #include "ash/shell.h"
@@ -29,6 +30,7 @@ ChromeVoxE2ETest = class extends E2ETestBase {
 
   /** @override */
   testGenPreamble() {
+    super.testGenPreamble();
     GEN(`
     auto allow = extension_l10n_util::AllowGzippedMessagesAllowedForTest();
     base::Closure load_cb =

chrome/browser/resources/chromeos/accessibility/common/testing/e2e_test_base.js

@@ -16,6 +16,20 @@ E2ETestBase = class extends testing.Test {
     this.desktop_;
   }
 
+  /** @override */
+  testGenCppIncludes() {
+    GEN(`
+  #include "chrome/browser/speech/extension_api/tts_engine_extension_api.h"
+      `);
+  }
+
+  /** @override */
+  testGenPreamble() {
+    GEN(`
+    TtsExtensionEngine::GetInstance()->DisableBuiltInTTSEngineForTesting();
+      `);
+  }
+
   /**
    * Listens and waits for the first event on the given node of the given type.
    * @param {!chrome.automation.AutomationNode} node

chrome/browser/resources/chromeos/accessibility/select_to_speak/select_to_speak_e2e_test_base.js

@@ -10,6 +10,7 @@ GEN_INCLUDE(['../common/testing/e2e_test_base.js']);
 SelectToSpeakE2ETest = class extends E2ETestBase {
   /** @override */
   testGenCppIncludes() {
+    super.testGenCppIncludes();
     GEN(`
 #include "ash/accessibility/accessibility_delegate.h"
 #include "ash/keyboard/ui/keyboard_util.h"
@@ -24,6 +25,7 @@ SelectToSpeakE2ETest = class extends E2ETestBase {
 
   /** @override */
   testGenPreamble() {
+    super.testGenPreamble();
     GEN(`
     //keyboard::SetRequestedKeyboardState(keyboard::KEYBOARD_STATE_ENABLED);
     //ash::Shell::Get()->CreateKeyboard();

chrome/browser/resources/chromeos/accessibility/switch_access/switch_access_e2e_test_base.js

@@ -10,6 +10,7 @@ GEN_INCLUDE([
 SwitchAccessE2ETest = class extends E2ETestBase {
   /** @override */
   testGenCppIncludes() {
+    super.testGenCppIncludes();
     GEN(`
 #include "ash/accessibility/accessibility_delegate.h"
 #include "ash/shell.h"
@@ -24,6 +25,7 @@ SwitchAccessE2ETest = class extends E2ETestBase {
 
   /** @override */
   testGenPreamble() {
+    super.testGenPreamble();
     GEN(`
   base::Closure load_cb =
       base::Bind(&chromeos::AccessibilityManager::SetSwitchAccessEnabled,

chrome/browser/speech/extension_api/tts_engine_extension_api.cc

@@ -329,6 +329,9 @@ void TtsExtensionEngine::Resume(content::TtsUtterance* utterance) {
 
 bool TtsExtensionEngine::LoadBuiltInTtsEngine(
     content::BrowserContext* browser_context) {
+  if (disable_built_in_tts_engine_for_testing_)
+    return false;
+
 #if defined(OS_CHROMEOS)
   Profile* profile = Profile::FromBrowserContext(browser_context);
 

chrome/browser/speech/extension_api/tts_engine_extension_api.h

@@ -36,6 +36,13 @@ class TtsExtensionEngine : public content::TtsEngineDelegate {
   void Pause(content::TtsUtterance* utterance) override;
   void Resume(content::TtsUtterance* utterance) override;
   bool LoadBuiltInTtsEngine(content::BrowserContext* browser_context) override;
+
+  void DisableBuiltInTTSEngineForTesting() {
+    disable_built_in_tts_engine_for_testing_ = true;
+  }
+
+ private:
+  bool disable_built_in_tts_engine_for_testing_ = false;
 };
 
 // Function that allows tts engines to update its list of supported voices at