[ios] Moves the Find in Page APIs into FindTabHelper.

ios/chrome/browser/find_in_page/find_tab_helper.mm

 // Copyright 2017 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.
 
 #import "ios/chrome/browser/find_in_page/find_tab_helper.h"
 
 #import "ios/chrome/browser/find_in_page/find_in_page_controller.h"
+#import "ios/chrome/browser/find_in_page/find_in_page_model.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
 DEFINE_WEB_STATE_USER_DATA_KEY(FindTabHelper);
 
 // static
 void FindTabHelper::CreateForWebState(
     web::WebState* web_state,
     id<FindInPageControllerDelegate> controller_delegate) {
   DCHECK(web_state);
   if (!FromWebState(web_state)) {
     web_state->SetUserData(UserDataKey(),
                            new FindTabHelper(web_state, controller_delegate));
   }
 }
 
 FindTabHelper::FindTabHelper(
     web::WebState* web_state,
-    id<FindInPageControllerDelegate> controller_delegate) {
-  controller_ =
-      [[FindInPageController alloc] initWithWebState:web_state
-                                            delegate:controller_delegate];
+    id<FindInPageControllerDelegate> controller_delegate)
+    : web::WebStateObserver(web_state) {
+  controller_.reset([[FindInPageController alloc]
+      initWithWebState:web_state
+              delegate:controller_delegate]);
 }
 
 FindTabHelper::~FindTabHelper() {}
 
-FindInPageController* FindTabHelper::GetController() {
-  return controller_;
+void FindTabHelper::StartFinding(NSString* search_term,
+                                 FindInPageCompletionBlock completion) {
+  [controller_ findStringInPage:search_term
+              completionHandler:^{
+                FindInPageModel* model = controller_.get().findInPageModel;
+                completion(model);
+              }];
+}
+
+void FindTabHelper::ContinueFinding(FindDirection direction,
+                                    FindInPageCompletionBlock completion) {
+  FindInPageModel* model = controller_.get().findInPageModel;
+
+  if (direction == FORWARD) {
+    [controller_ findNextStringInPageWithCompletionHandler:^{
+      completion(model);
+    }];
+
+  } else if (direction == REVERSE) {
+    [controller_ findPreviousStringInPageWithCompletionHandler:^{
+      completion(model);
+    }];
+
+  } else {
+    NOTREACHED();
+  }
+}
+
+void FindTabHelper::StopFinding(ProceduralBlock completion) {
+  [controller_ disableFindInPageWithCompletionHandler:completion];
+  SetFindUIActive(false);
+}
+
+FindInPageModel* FindTabHelper::GetFindResult() const {
+  return controller_.get().findInPageModel;
+}
+
+bool FindTabHelper::CurrentPageSupportsFindInPage() const {
+  return [controller_ canFindInPage];
+}
+
+bool FindTabHelper::IsFindUIActive() const {
+  return controller_.get().findInPageModel.enabled;
+}
+
+void FindTabHelper::SetFindUIActive(bool active) {
+  controller_.get().findInPageModel.enabled = active;
+}
+
+void FindTabHelper::PersistSearchTerm() {
+  [controller_ saveSearchTerm];
+}
+
+void FindTabHelper::RestoreSearchTerm() {
+  [controller_ restoreSearchTerm];
 }
 
 void FindTabHelper::NavigationItemCommitted(
     const web::LoadCommittedDetails& load_details) {
-  [controller_ disableFindInPageWithCompletionHandler:nil];
+  StopFinding(nil);
 }
 
 void FindTabHelper::WebStateDestroyed() {
   [controller_ detachFromWebState];
 }