From 451065790761eb16157922ddf51c9b581dcf5ed7 Mon Sep 17 00:00:00 2001
From: David Baron <dbaron@chromium.org>
Date: Sun, 19 Jul 2026 06:47:30 -0700
Subject: [PATCH] Set FocusType more carefully when forwarding clicks from <label>.

Both the fix and the test are AI-authored, though from different AI
tools.  (I shortened a verbose code comment in the fix and reduced
overuse of the auto keyword in the test.)

Fixed: 533075126
Change-Id: I289f8f0d7c129776165ea6cfb502498c414cd706
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/8115027
Reviewed-by: Mason Freed <masonf@chromium.org>
Commit-Queue: David Baron <dbaron@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1664455}
---

diff --git a/third_party/blink/renderer/core/html/forms/html_label_element.cc b/third_party/blink/renderer/core/html/forms/html_label_element.cc
index a5a5d07..d1064db 100644
--- a/third_party/blink/renderer/core/html/forms/html_label_element.cc
+++ b/third_party/blink/renderer/core/html/forms/html_label_element.cc
@@ -260,8 +260,13 @@
       // In case of double click or triple click, selection will be there,
       // so do not focus the control element.
       if (!is_label_text_selected) {
+        // Set focus_type so that label.click() from script can't set
+        // WasLastFocusFromUserGesture.
+        const mojom::blink::FocusType focus_type =
+            evt.isTrusted() ? mojom::blink::FocusType::kMouse
+                            : mojom::blink::FocusType::kScript;
         element->Focus(FocusParams(SelectionBehaviorOnFocus::kRestore,
-                                   mojom::blink::FocusType::kMouse, nullptr,
+                                   focus_type, nullptr,
                                    FocusOptions::Create()));
       }
     }
diff --git a/third_party/blink/renderer/core/html/forms/html_label_element_test.cc b/third_party/blink/renderer/core/html/forms/html_label_element_test.cc
index 8565b7da..575f982a 100644
--- a/third_party/blink/renderer/core/html/forms/html_label_element_test.cc
+++ b/third_party/blink/renderer/core/html/forms/html_label_element_test.cc
@@ -6,6 +6,7 @@
 
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/blink/renderer/core/dom/document.h"
+#include "third_party/blink/renderer/core/dom/events/simulated_click_options.h"
 #include "third_party/blink/renderer/core/testing/page_test_base.h"
 
 namespace blink {
@@ -74,4 +75,31 @@
   EXPECT_EQ("", label->TextContentExcludingLabelable().StripWhiteSpace());
 }
 
+TEST_F(HTMLLabelElementTest, WasLastFocusFromUserGesture) {
+  SetBodyInnerHTML(R"HTML(
+    <label id=label1 for=input1></label>
+    <input id=input1>
+    <label id=label2 for=input2></label>
+    <input id=input2>
+  )HTML");
+  HTMLLabelElement* label1 = To<HTMLLabelElement>(
+      GetDocument().getElementById(AtomicString("label1")));
+  Element* input1 = GetDocument().getElementById(AtomicString("input1"));
+  Element* label2 = GetDocument().getElementById(AtomicString("label2"));
+  Element* input2 = GetDocument().getElementById(AtomicString("input2"));
+
+  // Untrusted click (such as label.click() from script) should not set
+  // WasLastFocusFromUserGesture().
+  label1->click();
+  EXPECT_EQ(input1, GetDocument().FocusedElement());
+  EXPECT_FALSE(input1->WasLastFocusFromUserGesture());
+
+  // Trusted click (such as user interaction) should set
+  // WasLastFocusFromUserGesture().
+  label2->DispatchSimulatedClick(nullptr,
+                                 SimulatedClickCreationScope::kFromUserAgent);
+  EXPECT_EQ(input2, GetDocument().FocusedElement());
+  EXPECT_TRUE(input2->WasLastFocusFromUserGesture());
+}
+
 }  // namespace blink

diff --git a/third_party/blink/renderer/core/html/forms/html_label_element_test.cc b/third_party/blink/renderer/core/html/forms/html_label_element_test.cc
index 8565b7da..575f982a 100644
--- a/third_party/blink/renderer/core/html/forms/html_label_element_test.cc
+++ b/third_party/blink/renderer/core/html/forms/html_label_element_test.cc
@@ -6,6 +6,7 @@
 
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/blink/renderer/core/dom/document.h"
+#include "third_party/blink/renderer/core/dom/events/simulated_click_options.h"
 #include "third_party/blink/renderer/core/testing/page_test_base.h"
 
 namespace blink {
@@ -74,4 +75,31 @@
   EXPECT_EQ("", label->TextContentExcludingLabelable().StripWhiteSpace());
 }
 
+TEST_F(HTMLLabelElementTest, WasLastFocusFromUserGesture) {
+  SetBodyInnerHTML(R"HTML(
+    <label id=label1 for=input1></label>
+    <input id=input1>
+    <label id=label2 for=input2></label>
+    <input id=input2>
+  )HTML");
+  HTMLLabelElement* label1 = To<HTMLLabelElement>(
+      GetDocument().getElementById(AtomicString("label1")));
+  Element* input1 = GetDocument().getElementById(AtomicString("input1"));
+  Element* label2 = GetDocument().getElementById(AtomicString("label2"));
+  Element* input2 = GetDocument().getElementById(AtomicString("input2"));
+
+  // Untrusted click (such as label.click() from script) should not set
+  // WasLastFocusFromUserGesture().
+  label1->click();
+  EXPECT_EQ(input1, GetDocument().FocusedElement());
+  EXPECT_FALSE(input1->WasLastFocusFromUserGesture());
+
+  // Trusted click (such as user interaction) should set
+  // WasLastFocusFromUserGesture().
+  label2->DispatchSimulatedClick(nullptr,
+                                 SimulatedClickCreationScope::kFromUserAgent);
+  EXPECT_EQ(input2, GetDocument().FocusedElement());
+  EXPECT_TRUE(input2->WasLastFocusFromUserGesture());
+}
+
 }  // namespace blink