Implement search engine auto switch when entering or leaving some locale

chrome/browser/android/locale/special_locale_handler.cc

 // Copyright (c) 2016 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 "chrome/browser/android/locale/special_locale_handler.h"
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_string.h"
 #include "base/android/jni_weak_ref.h"
 #include "base/memory/ptr_util.h"
@@ skipping 94 matching lines @@
   }
 
   TemplateURL* turl =
       FindURLByPrepopulateID(template_url_service_->GetTemplateURLs(),
                              GetDesignatedPrepopulatedIdForLocale(locale_));
   if (turl) {
     template_url_service_->SetUserSelectedDefaultSearchProvider(turl);
   }
 }
 
+void SpecialLocaleHandler::SetGoogleAsDefaultSearch(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj) {
+  // If the user has changed his default search provider, no-op.
+  TemplateURL* current_dsp = template_url_service_->GetDefaultSearchProvider();
+  if (!current_dsp ||
+      current_dsp->prepopulate_id() !=
+          GetDesignatedPrepopulatedIdForLocale(locale_)) {
+    return;
+  }
+
+  TemplateURL* turl =
+      FindURLByPrepopulateID(template_url_service_->GetTemplateURLs(),
+                             TemplateURLPrepopulateData::google.id);
+  if (turl) {
+    template_url_service_->SetUserSelectedDefaultSearchProvider(turl);
+  }
+}
+
 SpecialLocaleHandler::~SpecialLocaleHandler() {}
 
 // static
 bool RegisterSpecialLocaleHandler(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }