Implement native functions to query custom search engines for Android

1. Enable SearchEngineTabHelper on Android to auto-detect and fetch OpenSearch description document.
2. Add native function to retrieve recent visited search engines.
3. Allow recent visited search engine to be selected as default search engine.

BUG=348360

Review-Url: https://codereview.chromium.org/2349473002
Cr-Commit-Position: refs/heads/master@{#419569}

chrome/android/java/src/org/chromium/chrome/browser/search_engines/TemplateUrlService.java

@@ -47,16 +47,17 @@ public class TemplateUrlService {
     public static class TemplateUrl {
         private final int mIndex;
         private final String mShortName;
+        private boolean mIsPrepopulated;
 
         @CalledByNative("TemplateUrl")
-        public static TemplateUrl create(
-                int id, String shortName) {
-            return new TemplateUrl(id, shortName);
+        public static TemplateUrl create(int id, String shortName, boolean isPrepopulated) {
+            return new TemplateUrl(id, shortName, isPrepopulated);
         }
 
-        public TemplateUrl(int index, String shortName) {
+        public TemplateUrl(int index, String shortName, boolean isPrepopulated) {
             mIndex = index;
             mShortName = shortName;
+            mIsPrepopulated = isPrepopulated;
         }
 
         public int getIndex() {
@@ -128,9 +129,8 @@ public class TemplateUrlService {
         int templateUrlCount = nativeGetTemplateUrlCount(mNativeTemplateUrlServiceAndroid);
         List<TemplateUrl> templateUrls = new ArrayList<TemplateUrl>(templateUrlCount);
         for (int i = 0; i < templateUrlCount; i++) {
-            TemplateUrl templateUrl = nativeGetPrepopulatedTemplateUrlAt(
-                    mNativeTemplateUrlServiceAndroid, i);
-            if (templateUrl != null) {
+            TemplateUrl templateUrl = nativeGetTemplateUrlAt(mNativeTemplateUrlServiceAndroid, i);
+            if (templateUrl != null && templateUrl.mIsPrepopulated) {
                 templateUrls.add(templateUrl);
             }
         }
@@ -176,8 +176,7 @@ public class TemplateUrlService {
         assert defaultSearchEngineIndex < nativeGetTemplateUrlCount(
                 mNativeTemplateUrlServiceAndroid);
 
-        return nativeGetPrepopulatedTemplateUrlAt(
-                mNativeTemplateUrlServiceAndroid, defaultSearchEngineIndex);
+        return nativeGetTemplateUrlAt(mNativeTemplateUrlServiceAndroid, defaultSearchEngineIndex);
     }
 
     public void setSearchEngine(int selectedIndex) {
@@ -306,8 +305,7 @@ public class TemplateUrlService {
     private native void nativeLoad(long nativeTemplateUrlServiceAndroid);
     private native boolean nativeIsLoaded(long nativeTemplateUrlServiceAndroid);
     private native int nativeGetTemplateUrlCount(long nativeTemplateUrlServiceAndroid);
-    private native TemplateUrl nativeGetPrepopulatedTemplateUrlAt(
-            long nativeTemplateUrlServiceAndroid, int i);
+    private native TemplateUrl nativeGetTemplateUrlAt(long nativeTemplateUrlServiceAndroid, int i);
     private native void nativeSetUserSelectedDefaultSearchProvider(
             long nativeTemplateUrlServiceAndroid, int selectedIndex);
     private native int nativeGetDefaultSearchProvider(long nativeTemplateUrlServiceAndroid);

chrome/browser/search_engines/template_url_service_android.cc

@@ -65,8 +65,6 @@ void TemplateUrlServiceAndroid::SetUserSelectedDefaultSearchProvider(
       "Wrong index for search engine";
 
   TemplateURL* template_url = template_urls[selected_index_size_t];
-  DCHECK_GT(template_url->prepopulate_id(), 0) <<
-      "Tried to select non-prepopulated search engine";
   template_url_service_->SetUserSelectedDefaultSearchProvider(template_url);
 }
 
@@ -123,18 +121,15 @@ jboolean TemplateUrlServiceAndroid::IsDefaultSearchEngineGoogle(
 }
 
 base::android::ScopedJavaLocalRef<jobject>
-TemplateUrlServiceAndroid::GetPrepopulatedTemplateUrlAt(
-    JNIEnv* env,
-    const JavaParamRef<jobject>& obj,
-    jint index) {
+TemplateUrlServiceAndroid::GetTemplateUrlAt(JNIEnv* env,
+                                            const JavaParamRef<jobject>& obj,
+                                            jint index) {
   TemplateURL* template_url = template_url_service_->GetTemplateURLs()[index];
-  if (!IsPrepopulatedTemplate(template_url) &&
-      !template_url->created_by_policy())
-   return ScopedJavaLocalRef<jobject>();
-
   return Java_TemplateUrl_create(
       env, index,
-      base::android::ConvertUTF16ToJavaString(env, template_url->short_name()));
+      base::android::ConvertUTF16ToJavaString(env, template_url->short_name()),
+      IsPrepopulatedTemplate(template_url) ||
+          template_url->created_by_policy());
 }
 
 bool TemplateUrlServiceAndroid::IsPrepopulatedTemplate(TemplateURL* url) {

chrome/browser/search_engines/template_url_service_android.h

@@ -35,7 +35,7 @@ class TemplateUrlServiceAndroid : public TemplateURLServiceObserver {
                            const base::android::JavaParamRef<jobject>& obj);
   jboolean IsLoaded(JNIEnv* env,
                     const base::android::JavaParamRef<jobject>& obj);
-  base::android::ScopedJavaLocalRef<jobject> GetPrepopulatedTemplateUrlAt(
+  base::android::ScopedJavaLocalRef<jobject> GetTemplateUrlAt(
       JNIEnv* env,
       const base::android::JavaParamRef<jobject>& obj,
       jint index);

chrome/browser/ui/tab_helpers.cc

@@ -46,6 +46,7 @@
 #include "chrome/browser/ui/pdf/chrome_pdf_web_contents_helper_client.h"
 #include "chrome/browser/ui/prefs/prefs_tab_helper.h"
 #include "chrome/browser/ui/search/search_tab_helper.h"
+#include "chrome/browser/ui/search_engines/search_engine_tab_helper.h"
 #include "chrome/browser/ui/tab_contents/core_tab_helper.h"
 #include "chrome/browser/ui/tab_dialogs.h"
 #include "chrome/common/chrome_switches.h"
@@ -81,7 +82,6 @@
 #include "chrome/browser/ui/bookmarks/bookmark_tab_helper.h"
 #include "chrome/browser/ui/hung_plugin_tab_helper.h"
 #include "chrome/browser/ui/sad_tab_helper.h"
-#include "chrome/browser/ui/search_engines/search_engine_tab_helper.h"
 #include "chrome/browser/ui/sync/tab_contents_synced_tab_delegate.h"
 #include "components/pdf/browser/pdf_web_contents_helper.h"
 #include "components/web_modal/web_contents_modal_dialog_manager.h"
@@ -187,6 +187,7 @@ void TabHelpers::AttachTabHelpers(WebContents* web_contents) {
   prerender::PrerenderTabHelper::CreateForWebContents(web_contents);
   PreviewsInfoBarTabHelper::CreateForWebContents(web_contents);
   SearchTabHelper::CreateForWebContents(web_contents);
+  SearchEngineTabHelper::CreateForWebContents(web_contents);
   ChromeSecurityStateModelClient::CreateForWebContents(web_contents);
   if (SiteEngagementService::IsEnabled())
     SiteEngagementService::Helper::CreateForWebContents(web_contents);
@@ -228,7 +229,6 @@ void TabHelpers::AttachTabHelpers(WebContents* web_contents) {
   PluginObserver::CreateForWebContents(web_contents);
   SadTabHelper::CreateForWebContents(web_contents);
   safe_browsing::SafeBrowsingTabObserver::CreateForWebContents(web_contents);
-  SearchEngineTabHelper::CreateForWebContents(web_contents);
   TabContentsSyncedTabDelegate::CreateForWebContents(web_contents);
   TabDialogs::CreateForWebContents(web_contents);
   ThumbnailTabHelper::CreateForWebContents(web_contents);