[Android] Allow setting recently visited search engines as default search engine

chrome/browser/search_engines/template_url_service_android.h

 // 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.
 
 #ifndef CHROME_BROWSER_SEARCH_ENGINES_TEMPLATE_URL_SERVICE_ANDROID_H_
 #define CHROME_BROWSER_SEARCH_ENGINES_TEMPLATE_URL_SERVICE_ANDROID_H_
 
 #include <memory>
 
 #include "base/android/jni_weak_ref.h"
 #include "base/android/scoped_java_ref.h"
 #include "base/macros.h"
 #include "components/search_engines/template_url_service.h"
 #include "components/search_engines/template_url_service_observer.h"
 
 class TemplateURL;
 
 
 // Android wrapper of the TemplateUrlService which provides access from the Java
 // layer. Note that on Android, there's only a single profile, and therefore
 // a single instance of this wrapper.
 class TemplateUrlServiceAndroid : public TemplateURLServiceObserver {
  public:
   TemplateUrlServiceAndroid(JNIEnv* env, jobject obj);
 
   void Load(JNIEnv* env, const base::android::JavaParamRef<jobject>& obj);
   void SetUserSelectedDefaultSearchProvider(
       JNIEnv* env,
       const base::android::JavaParamRef<jobject>& obj,
-      jint selected_index);
-  jint GetDefaultSearchProvider(
+      const base::android::JavaParamRef<jstring>& jkeyword);
+
+  // Updates |template_urls_| and returns the index of the default search
+  // provider
+  // within |it.

[Peter Kasting, 2016/11/23 21:30:27]

This comment lies, since it doesn't update this variable.

In general, I'd avoid talking about |template_urls_| anyway in the public API
comments, since that's an implementation detail.

[ltian, 2016/11/29 02:44:03]

Sorry I forgot to update the comment. I think for current design, the function
name is pretty clear, so there is no need for any comment.

+  jint GetDefaultSearchProviderIndex(
       JNIEnv* env,
-      const base::android::JavaParamRef<jobject>& obj);
-  jint GetTemplateUrlCount(JNIEnv* env,
-                           const base::android::JavaParamRef<jobject>& obj);
+      const base::android::JavaParamRef<jobject>& obj) const;
+
+  jint GetTemplateUrlCount(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj) const;
   jboolean IsLoaded(JNIEnv* env,
                     const base::android::JavaParamRef<jobject>& obj);
   base::android::ScopedJavaLocalRef<jobject> GetTemplateUrlAt(
       JNIEnv* env,
       const base::android::JavaParamRef<jobject>& obj,
-      jint index);
+      jint index) const;
   jboolean IsSearchProviderManaged(
       JNIEnv* env,
       const base::android::JavaParamRef<jobject>& obj);
   jboolean IsSearchByImageAvailable(
       JNIEnv* env,
       const base::android::JavaParamRef<jobject>& obj);
   jboolean IsDefaultSearchEngineGoogle(
       JNIEnv* env,
       const base::android::JavaParamRef<jobject>& obj);
   base::android::ScopedJavaLocalRef<jstring> GetUrlForSearchQuery(
@@ skipping 12 matching lines @@
   base::android::ScopedJavaLocalRef<jstring> GetUrlForContextualSearchQuery(
       JNIEnv* env,
       const base::android::JavaParamRef<jobject>& obj,
       const base::android::JavaParamRef<jstring>& jquery,
       const base::android::JavaParamRef<jstring>& jalternate_term,
       jboolean jshould_prefetch,
       const base::android::JavaParamRef<jstring>& jprotocol_version);
   base::android::ScopedJavaLocalRef<jstring> GetSearchEngineUrlFromTemplateUrl(
       JNIEnv* env,
       const base::android::JavaParamRef<jobject>& obj,
-      jint index);
+      const base::android::JavaParamRef<jstring>& jkeyword);
 
   static bool Register(JNIEnv* env);
 
  private:
   ~TemplateUrlServiceAndroid() override;
 
-  bool IsPrepopulatedTemplate(TemplateURL* url);
-
   void OnTemplateURLServiceLoaded();
 
   // TemplateUrlServiceObserver:
   void OnTemplateURLServiceChanged() override;
 
+  void LoadTemplateURLs();

[Peter Kasting, 2016/11/23 21:30:27]

Nit: Add comments about what this does.

[ltian, 2016/11/29 02:44:03]

Done.

+
   JavaObjectWeakGlobalRef weak_java_obj_;
 
   // Pointer to the TemplateUrlService for the main profile.
   TemplateURLService* template_url_service_;
 
   std::unique_ptr<TemplateURLService::Subscription> template_url_subscription_;
 
+  std::vector<TemplateURL*> template_urls_;

[Peter Kasting, 2016/11/23 21:30:27]

Nit: Add comments about why we need to cache this.

[ltian, 2016/11/29 02:44:03]

Done.

+
+  size_t default_search_provider_index_;
+
   DISALLOW_COPY_AND_ASSIGN(TemplateUrlServiceAndroid);
 };
 
 #endif  // CHROME_BROWSER_SEARCH_ENGINES_TEMPLATE_URL_SERVICE_ANDROID_H_