Add build flag to disable hotwording.

Hotwording downloads a shared module from the web store containing a NaCl module. There is a desire to build and distribute Chromium without this happening. This change adds an "enable_hotwording" build flag that is enabled by default, but can be disabled at compile time.

BUG=491435

Review URL: https://codereview.chromium.org/1160243004

Cr-Commit-Position: refs/heads/master@{#333548}

build/common.gypi

diff --git a/build/common.gypi b/build/common.gypi
index 6e8f853d..02dd63e 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -416,6 +416,9 @@
       # Web speech is enabled by default. Set to 0 to disable.
       'enable_web_speech%': 1,
 
+      # 'Ok Google' hotwording is enabled by default. Set to 0 to disable.
+      'enable_hotwording%': 1,
+
       # Notifications are compiled in by default. Set to 0 to disable.
       'notifications%' : 1,
 
@@ -1143,6 +1146,7 @@
     'configuration_policy%': '<(configuration_policy)',
     'safe_browsing%': '<(safe_browsing)',
     'enable_web_speech%': '<(enable_web_speech)',
+    'enable_hotwording%': '<(enable_hotwording)',
     'notifications%': '<(notifications)',
     'clang_use_chrome_plugins%': '<(clang_use_chrome_plugins)',
     'mac_want_real_dsym%': '<(mac_want_real_dsym)',

chrome/browser/BUILD.gn

diff --git a/chrome/browser/BUILD.gn b/chrome/browser/BUILD.gn
index 74971e6..18e43ec 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -19,6 +19,11 @@
   import("//build/config/linux/pkg_config.gni")
 }
 
+declare_args() {
+  # 'Ok Google' hotwording is enabled.
+  enable_hotwording = true
+}
+
 about_credits_file = "$target_gen_dir/about_credits.html"
 additional_modules_list_file =
     "$root_gen_dir/chrome/browser/internal/additional_modules_list.txt"
@@ -452,6 +457,10 @@
     }
   }
 
+  if (enable_hotwording) {
+    defines += [ "ENABLE_HOTWORDING" ]
+  }
+
   if (is_linux) {
     deps += [
       "//device/media_transfer_protocol",

chrome/browser/search/hotword_service.cc

diff --git a/chrome/browser/search/hotword_service.cc b/chrome/browser/search/hotword_service.cc
index d222b150..5b08027 100644
--- a/chrome/browser/search/hotword_service.cc
+++ b/chrome/browser/search/hotword_service.cc
@@ -639,7 +639,11 @@
 }
 
 bool HotwordService::IsHotwordAllowed() {
+#if defined(ENABLE_HOTWORDING)
   return DoesHotwordSupportLanguage(profile_);
+#else
+  return false;
+#endif
 }
 
 bool HotwordService::IsOptedIntoAudioLogging() {

chrome/browser/search/hotword_service_unittest.cc

diff --git a/chrome/browser/search/hotword_service_unittest.cc b/chrome/browser/search/hotword_service_unittest.cc
index 588706c..8444446 100644
--- a/chrome/browser/search/hotword_service_unittest.cc
+++ b/chrome/browser/search/hotword_service_unittest.cc
@@ -157,6 +157,7 @@
                             extension_misc::kHotwordSharedModuleId));
 
 TEST_P(HotwordServiceTest, IsHotwordAllowedLocale) {
+#if defined(ENABLE_HOTWORDING)
   TestingProfile::Builder profile_builder;
   scoped_ptr<TestingProfile> profile = profile_builder.Build();
 
@@ -187,6 +188,7 @@
   Profile* otr_profile = profile->GetOffTheRecordProfile();
   SetApplicationLocale(otr_profile, "en");
   EXPECT_FALSE(HotwordServiceFactory::IsHotwordAllowed(otr_profile));
+#endif  // defined(ENABLE_HOTWORDING)
 }
 
 TEST_P(HotwordServiceTest, ShouldReinstallExtension) {
@@ -243,6 +245,7 @@
 }
 
 TEST_P(HotwordServiceTest, UninstallReinstallTriggeredCorrectly) {
+#if defined(ENABLE_HOTWORDING)
   InitializeEmptyExtensionService();
   service_->Init();
 
@@ -313,6 +316,7 @@
   EXPECT_TRUE(HotwordServiceFactory::IsHotwordAllowed(profile()));
   EXPECT_FALSE(hotword_service->MaybeReinstallHotwordExtension());
   EXPECT_EQ(1, hotword_service->uninstall_count());  // no change
+#endif  // defined(ENABLE_HOTWORDING)
 }
 
 TEST_P(HotwordServiceTest, DisableAlwaysOnOnLanguageChange) {

chrome/chrome_browser.gypi

diff --git a/chrome/chrome_browser.gypi b/chrome/chrome_browser.gypi
index 5ba1538..9f22a44f 100644
--- a/chrome/chrome_browser.gypi
+++ b/chrome/chrome_browser.gypi
@@ -3589,6 +3589,9 @@
         ['enable_session_service==1', {
           'sources': [ '<@(chrome_browser_session_service_sources)' ],
         }],
+        ['enable_hotwording==1', {
+          'defines': [ 'ENABLE_HOTWORDING' ],
+        }],
         ['OS!="android" and OS!="ios" and chromeos==0', {
           'sources': [ '<@(chrome_browser_desktop_sources)' ],
         }],