[ios] Snapshot for WebState

ios/web/public/test/fakes/test_web_state.mm

Index: ios/web/public/test/fakes/test_web_state.mm
diff --git a/ios/web/public/test/fakes/test_web_state.mm b/ios/web/public/test/fakes/test_web_state.mm
index 9c268874967e742a94a6ae680562f19ed78fccb5..97b631d3edb43872d941af58fee98f34b2277666 100644
--- a/ios/web/public/test/fakes/test_web_state.mm
+++ b/ios/web/public/test/fakes/test_web_state.mm
@@ -6,9 +6,12 @@
 
 #include <stdint.h>
 
+#include "base/bind.h"
 #include "base/callback.h"
+#include "base/threading/sequenced_task_runner_handle.h"
 #import "ios/web/public/web_state/ui/crw_content_view.h"
 #include "ios/web/public/web_state/web_state_observer.h"
+#include "ui/gfx/image/image.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
@@ -230,6 +233,12 @@ bool TestWebState::HasOpener() const {
   return false;
 }
 
+void TestWebState::TakeSnapshot(const SnapshotCallback& callback,
+                                CGSize target_size) const {
+  base::SequencedTaskRunnerHandle::Get()->PostTask(
+      FROM_HERE, base::Bind(callback, gfx::Image()));
+}
+
 base::WeakPtr<WebState> TestWebState::AsWeakPtr() {
   NOTREACHED();
   return base::WeakPtr<WebState>();