[Autofill Assistant] Implement focus on element.

R=gogerald@chromium.org

Bug: 806868
Change-Id: I6e2b277d3083645c7967cc3a1a481c8bf645eebd
Reviewed-on: https://chromium-review.googlesource.com/1233739Reviewed-by: Ganggui Tang <gogerald@chromium.org>
Commit-Queue: Ganggui Tang <gogerald@chromium.org>
Cr-Commit-Position: refs/heads/master@{#592433}

components/autofill_assistant/browser/web_controller.cc

@@ -84,7 +84,7 @@ void WebController::OnScrollIntoView(
     std::unique_ptr<runtime::CallFunctionOnResult> result) {
   devtools_client_->GetRuntime()->Disable();
   if (!result || result->HasExceptionDetails()) {
-    DLOG(ERROR) << "Failed to scroll the element into view to click.";
+    DLOG(ERROR) << "Failed to scroll the element.";
     OnResult(false, std::move(callback));
     return;
   }
@@ -295,6 +295,42 @@ void WebController::OnResult(bool result,
   std::move(callback).Run(result);
 }
 
+void WebController::OnFindElementForFocusElement(
+    base::OnceCallback<void(bool)> callback,
+    std::string object_id) {
+  if (object_id.empty()) {
+    DLOG(ERROR) << "Failed to find the element to focus on.";
+    OnResult(false, std::move(callback));
+    return;
+  }
+
+  std::vector<std::unique_ptr<runtime::CallArgument>> argument;
+  argument.emplace_back(
+      runtime::CallArgument::Builder().SetObjectId(object_id).Build());
+  devtools_client_->GetRuntime()->Enable();
+  devtools_client_->GetRuntime()->CallFunctionOn(
+      runtime::CallFunctionOnParams::Builder()
+          .SetObjectId(object_id)
+          .SetArguments(std::move(argument))
+          .SetFunctionDeclaration(std::string(kScrollIntoViewScript))
+          .SetReturnByValue(true)
+          .Build(),
+      base::BindOnce(&WebController::OnFocusElement,
+                     weak_ptr_factory_.GetWeakPtr(), std::move(callback)));
+}
+
+void WebController::OnFocusElement(
+    base::OnceCallback<void(bool)> callback,
+    std::unique_ptr<runtime::CallFunctionOnResult> result) {
+  devtools_client_->GetRuntime()->Disable();
+  if (!result || result->HasExceptionDetails()) {
+    DLOG(ERROR) << "Failed to focus on element.";
+    OnResult(false, std::move(callback));
+    return;
+  }
+  OnResult(true, std::move(callback));
+}
+
 void WebController::FillAddressForm(const std::string& guid,
                                     const std::vector<std::string>& selectors,
                                     base::OnceCallback<void(bool)> callback) {
@@ -318,8 +354,11 @@ void WebController::SelectOption(const std::vector<std::string>& selectors,
 
 void WebController::FocusElement(const std::vector<std::string>& selectors,
                                  base::OnceCallback<void(bool)> callback) {
-  // TODO(crbug.com/806868): Implement focus on element operation.
-  std::move(callback).Run(true);
+  DCHECK(!selectors.empty());
+  FindElement(
+      selectors,
+      base::BindOnce(&WebController::OnFindElementForFocusElement,
+                     weak_ptr_factory_.GetWeakPtr(), std::move(callback)));
 }
 
 void WebController::GetFieldsValue(

components/autofill_assistant/browser/web_controller.h

@@ -122,6 +122,10 @@ class WebController {
       base::OnceCallback<void(std::string)> callback,
       std::unique_ptr<dom::PushNodesByBackendIdsToFrontendResult> result);
   void OnResult(bool result, base::OnceCallback<void(bool)> callback);
+  void OnFindElementForFocusElement(base::OnceCallback<void(bool)> callback,
+                                    std::string object_id);
+  void OnFocusElement(base::OnceCallback<void(bool)> callback,
+                      std::unique_ptr<runtime::CallFunctionOnResult> result);
 
   // Weak pointer is fine here since it must outlive this web controller, which
   // is guaranteed by the owner of this object.

components/autofill_assistant/browser/web_controller_browsertest.cc

@@ -5,6 +5,7 @@
 #include "base/bind.h"
 #include "components/autofill_assistant/browser/web_controller.h"
 #include "content/public/browser/web_contents.h"
+#include "content/public/test/browser_test_utils.h"
 #include "content/public/test/content_browser_test.h"
 #include "content/public/test/content_browser_test_utils.h"
 #include "content/shell/browser/shell.h"
@@ -83,6 +84,20 @@ class WebControllerBrowserTest : public content::ContentBrowserTest {
     }
   }
 
+  void FocusElement(const std::vector<std::string>& selectors) {
+    base::RunLoop run_loop;
+    web_controller_->FocusElement(
+        selectors,
+        base::BindOnce(&WebControllerBrowserTest::OnFocusElement,
+                       base::Unretained(this), run_loop.QuitClosure()));
+    run_loop.Run();
+  }
+
+  void OnFocusElement(base::Closure done_callback, bool result) {
+    ASSERT_TRUE(result);
+    std::move(done_callback).Run();
+  }
+
  private:
   std::unique_ptr<net::EmbeddedTestServer> http_server_;
   std::unique_ptr<autofill_assistant::WebController> web_controller_;
@@ -141,4 +156,52 @@ IN_PROC_BROWSER_TEST_F(WebControllerBrowserTest,
   selectors.emplace_back("#button");
   WaitForElementRemove(selectors);
 }
+
+IN_PROC_BROWSER_TEST_F(WebControllerBrowserTest, FocusElement) {
+  std::vector<std::string> selectors;
+  selectors.emplace_back("#iframe");
+  selectors.emplace_back("#focus");
+
+  // The element is not visible initially.
+  const std::string checkNotVisibleScript = R"(
+      let iframe = document.querySelector("#iframe");
+      let div = iframe.contentDocument.querySelector("#focus");
+      let iframeRect = iframe.getBoundingClientRect();
+      let divRect = div.getBoundingClientRect();
+      iframeRect.y + divRect.y > window.innerHeight;
+  )";
+  EXPECT_EQ(true, content::EvalJs(shell(), checkNotVisibleScript));
+  FocusElement(selectors);
+
+  // Verify that the scroll moved the div in the iframe into view.
+  const std::string checkVisibleScript = R"(
+    const scrollTimeoutMs = 500;
+    var timer = null;
+
+    function check() {
+      let iframe = document.querySelector("#iframe");
+      let div = iframe.contentDocument.querySelector("#focus");
+      let iframeRect = iframe.getBoundingClientRect();
+      let divRect = div.getBoundingClientRect();
+      return iframeRect.y + divRect.y < window.innerHeight;
+    }
+    function onScrollDone() {
+      window.removeEventListener("scroll", onScroll);
+      domAutomationController.send(check());
+    }
+    function onScroll(e) {
+      if (timer != null) {
+        clearTimeout(timer);
+      }
+      timer = setTimeout(onScrollDone, scrollTimeoutMs);
+    }
+    if (check()) {
+      // Scrolling finished before this script started. Just return the result.
+      domAutomationController.send(true);
+    } else {
+      window.addEventListener("scroll", onScroll);
+    }
+  )";
+  EXPECT_EQ(true, content::EvalJsWithManualReply(shell(), checkVisibleScript));
+}
 }  // namespace

components/test/data/autofill_assistant/autofill_assistant_target_website_iframe.html

@@ -25,6 +25,12 @@ found in the LICENSE file.
         button.parentNode.removeChild(button);
       }
     </script>
+
+    <style>
+      #full_height_section {
+        height: 100vh;
+      }
+    </style>
   </head>
 
   <body onload="createShadowDom()">
@@ -58,5 +64,15 @@ found in the LICENSE file.
 
     <hr>
     <div id="shadowsection"></div>
+
+    <!--
+    Intentionally make this section has the full height of the window
+    to force scroll when operating on the elements below not in this
+    section.
+    -->
+    <div id="full_height_section">
+      <p>Blank Section
+    </div>
+    <div id="focus">Hidden Text</div>
   </body>
-</html>
+</html>
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