[ios] Snapshot for WebState

ios/web/web_state/web_state_impl.mm

 // Copyright 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.
 
 #import "ios/web/web_state/web_state_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
+#include "base/bind.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/sys_string_conversions.h"
+#include "base/threading/sequenced_task_runner_handle.h"
 #import "ios/web/interstitials/web_interstitial_impl.h"
 #import "ios/web/navigation/crw_session_controller.h"
 #import "ios/web/navigation/legacy_navigation_manager_impl.h"
 #import "ios/web/navigation/navigation_item_impl.h"
 #import "ios/web/navigation/session_storage_builder.h"
 #include "ios/web/public/browser_state.h"
 #import "ios/web/public/crw_session_storage.h"
 #import "ios/web/public/java_script_dialog_presenter.h"
 #import "ios/web/public/navigation_item.h"
 #include "ios/web/public/url_util.h"
 #import "ios/web/public/web_client.h"
 #import "ios/web/public/web_state/context_menu_params.h"
 #import "ios/web/public/web_state/ui/crw_content_view.h"
 #import "ios/web/public/web_state/web_state_delegate.h"
 #include "ios/web/public/web_state/web_state_interface_provider.h"
 #include "ios/web/public/web_state/web_state_observer.h"
 #import "ios/web/public/web_state/web_state_policy_decider.h"
 #include "ios/web/public/web_thread.h"
 #include "ios/web/public/webui/web_ui_ios_controller.h"
 #include "ios/web/web_state/global_web_state_event_tracker.h"
 #import "ios/web/web_state/navigation_context_impl.h"
 #import "ios/web/web_state/session_certificate_policy_cache_impl.h"
 #import "ios/web/web_state/ui/crw_web_controller.h"
 #import "ios/web/web_state/ui/crw_web_controller_container_view.h"
 #include "ios/web/webui/web_ui_ios_controller_factory_registry.h"
 #include "ios/web/webui/web_ui_ios_impl.h"
 #include "net/http/http_response_headers.h"
+#include "ui/gfx/image/image.h"
 
 namespace web {
 
 /* static */
 std::unique_ptr<WebState> WebState::Create(const CreateParams& params) {
   std::unique_ptr<WebStateImpl> web_state(new WebStateImpl(params));
 
   // Initialize the new session.
   web_state->GetNavigationManagerImpl().InitializeSession();
 
@@ skipping 614 matching lines @@
 }
 
 id<CRWWebViewProxy> WebStateImpl::GetWebViewProxy() const {
   return [web_controller_ webViewProxy];
 }
 
 bool WebStateImpl::HasOpener() const {
   return created_with_opener_;
 }
 
+void WebStateImpl::TakeSnapshot(const SnapshotCallback& callback,
+                                CGSize target_size) const {
+  UIView* view = [web_controller_ view];
+  UIImage* snapshot = nil;
+  if (view && !CGRectIsEmpty(view.bounds)) {
+    CGFloat scaled_height =
+        view.bounds.size.height * target_size.width / view.bounds.size.width;
+    CGRect scaled_rect = CGRectMake(0, 0, target_size.width, scaled_height);
+    UIGraphicsBeginImageContextWithOptions(target_size, YES, 0);
+    [view drawViewHierarchyInRect:scaled_rect afterScreenUpdates:NO];
+    snapshot = UIGraphicsGetImageFromCurrentImageContext();
+    UIGraphicsEndImageContext();
+  }
+  base::SequencedTaskRunnerHandle::Get()->PostTask(
+      FROM_HERE, base::Bind(callback, gfx::Image(snapshot)));
+}
+
 void WebStateImpl::OnNavigationStarted(web::NavigationContext* context) {
   for (auto& observer : observers_)
     observer.DidStartNavigation(context);
 }
 
 void WebStateImpl::OnNavigationFinished(web::NavigationContext* context) {
   for (auto& observer : observers_)
     observer.DidFinishNavigation(context);
 }
 
@@ skipping 26 matching lines @@
     const LoadCommittedDetails& load_details) {
   for (auto& observer : observers_)
     observer.NavigationItemCommitted(load_details);
 }
 
 WebState* WebStateImpl::GetWebState() {
   return this;
 }
 
 }  // namespace web