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

chrome/browser/search_engines/template_url_service_android.h

Index: chrome/browser/search_engines/template_url_service_android.h
diff --git a/chrome/browser/search_engines/template_url_service_android.h b/chrome/browser/search_engines/template_url_service_android.h
index af5f38c08a212727731e298448ae5df747711b74..ef351d661d4f3df6f464c996ebec24d655c934fe 100644
--- a/chrome/browser/search_engines/template_url_service_android.h
+++ b/chrome/browser/search_engines/template_url_service_android.h
@@ -27,18 +27,24 @@ class TemplateUrlServiceAndroid : public TemplateURLServiceObserver {
   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);
@@ -71,20 +77,20 @@ class TemplateUrlServiceAndroid : public TemplateURLServiceObserver {
   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.
@@ -92,6 +98,10 @@ class TemplateUrlServiceAndroid : public TemplateURLServiceObserver {
 
   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);
 };