From e5dcea4a11199d00d7d41dca9d29f136b829117d Mon Sep 17 00:00:00 2001
From: Quentin Pubert <[email protected]>
Date: Fri, 22 May 2026 04:13:38 -0700
Subject: [PATCH] [iOS] Defer native UI presentation for background specialized downloads

This CL implements visibility checks in four specialized tab helpers:
- 1) VcardTabHelper
- 2) PassKitTabHelper
- 3) SafariDownloadTabHelper
- 4) ARQuickLookTabHelper

If a download completes or is triggered while the tab is in the
background, its presentation is deferred. The latest pending download's
native UI (contact card, passes sheet, mobileconfig alert, or AR model
preview) is presented immediately once the tab is brought back to the
foreground (receiving the WasShown observer callback). To prevent a
flood of multiple modal UI sheet overlays when switching back, only the
most recent pending download is kept per tab helper.

Bug: 513989973
Change-Id: Ifc21e86fb784fccb0a1ee0ae70b5a8aa7e5655b0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7859853
Auto-Submit: Quentin Pubert <[email protected]>
Commit-Queue: Quentin Pubert <[email protected]>
Reviewed-by: Olivier Robin <[email protected]>
Commit-Queue: Olivier Robin <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1634855}
---

diff --git a/ios/chrome/browser/download/coordinator/safari_download_coordinator_unittest.mm b/ios/chrome/browser/download/coordinator/safari_download_coordinator_unittest.mm
index 70bdadf..e2c71c2 100644
--- a/ios/chrome/browser/download/coordinator/safari_download_coordinator_unittest.mm
+++ b/ios/chrome/browser/download/coordinator/safari_download_coordinator_unittest.mm
@@ -20,6 +20,7 @@
 #import "ios/chrome/browser/shared/model/web_state_list/web_state_list.h"
 #import "ios/chrome/browser/shared/model/web_state_list/web_state_opener.h"
 #import "ios/chrome/test/scoped_key_window.h"
+#import "ios/web/public/test/fakes/fake_download_task.h"
 #import "ios/web/public/test/fakes/fake_web_state.h"
 #import "ios/web/public/test/web_task_environment.h"
 #import "net/base/apple/url_conversions.h"
@@ -83,6 +84,7 @@
     // SafariDownloadTabHelper instances once started.
     auto web_state = std::make_unique<web::FakeWebState>();
     auto* web_state_ptr = web_state.get();
+    web_state_ptr->WasShown();
     SafariDownloadTabHelper::CreateForWebState(web_state_ptr);
     browser_->GetWebStateList()->InsertWebState(std::move(web_state));
     [coordinator_ start];
@@ -241,4 +243,33 @@
       0);
 }
 
+// Tests that SafariDownloadTabHelper defers UI alert presentation when the
+// WebState is hidden.
+TEST_F(SafariDownloadCoordinatorTest,
+       DeferSafariDownloadPresentationWhenHidden) {
+  web::FakeWebState* fake_web_state = static_cast<web::FakeWebState*>(
+      browser_->GetWebStateList()->GetWebStateAt(0));
+  fake_web_state->WasHidden();
+
+  auto task = std::make_unique<web::FakeDownloadTask>(
+      GURL("https://test.test/mobileconfig"), kMobileConfigurationType);
+
+  // Start the download in tab helper.
+  tab_helper()->DownloadMobileConfig(std::move(task));
+
+  // The warning alert should not be presented while hidden.
+  EXPECT_FALSE(WaitUntilConditionOrTimeout(kWaitForUIElementTimeout, ^{
+    return [base_view_controller_.presentedViewController class] ==
+           [UIAlertController class];
+  }));
+
+  // Now show the web state. The warning alert should be presented.
+  fake_web_state->WasShown();
+
+  EXPECT_TRUE(WaitUntilConditionOrTimeout(kWaitForUIElementTimeout, ^{
+    return [base_view_controller_.presentedViewController class] ==
+           [UIAlertController class];
+  }));
+}
+
 }  // namespace
diff --git a/ios/chrome/browser/download/model/ar_quick_look_tab_helper.h b/ios/chrome/browser/download/model/ar_quick_look_tab_helper.h
index 56b543ca..f2a17b2 100644
--- a/ios/chrome/browser/download/model/ar_quick_look_tab_helper.h
+++ b/ios/chrome/browser/download/model/ar_quick_look_tab_helper.h
@@ -5,11 +5,14 @@
 #ifndef IOS_CHROME_BROWSER_DOWNLOAD_MODEL_AR_QUICK_LOOK_TAB_HELPER_H_
 #define IOS_CHROME_BROWSER_DOWNLOAD_MODEL_AR_QUICK_LOOK_TAB_HELPER_H_
 
-#include <memory>
+#import <memory>
+#import <optional>
 
-#include "base/memory/raw_ptr.h"
-#include "ios/web/public/download/download_task_observer.h"
-#include "ios/web/public/web_state_user_data.h"
+#import "base/memory/raw_ptr.h"
+#import "base/scoped_observation.h"
+#import "ios/web/public/download/download_task_observer.h"
+#import "ios/web/public/web_state_observer.h"
+#import "ios/web/public/web_state_user_data.h"
 
 @protocol ARQuickLookTabHelperDelegate;
 
@@ -48,6 +51,7 @@
 // TabHelper to download and preview USDZ format 3D models for AR.
 class ARQuickLookTabHelper
     : public web::DownloadTaskObserver,
+      public web::WebStateObserver,
       public web::WebStateUserData<ARQuickLookTabHelper> {
  public:
   ARQuickLookTabHelper(const ARQuickLookTabHelper&) = delete;
@@ -80,15 +84,32 @@
   // web::DownloadTaskObserver:
   void OnDownloadUpdated(web::DownloadTask* download_task) override;
 
+  // web::WebStateObserver overrides:
+  void WasShown(web::WebState* web_state) override;
+
   // Previews the downloaded USDZ file or confirms the download if download has
   // not started.
   void ConfirmOrPreviewDownload(web::DownloadTask* download_task);
 
+  // Structure to hold the metadata of an AR Quick Look preview that completed
+  // while the web state was hidden, allowing it to be deferred.
+  struct PendingARPreview {
+    NSURL* file_url;
+    NSURL* canonical_url;
+    bool allow_content_scaling;
+  };
+
   raw_ptr<web::WebState> web_state_ = nullptr;
   __weak id<ARQuickLookTabHelperDelegate> delegate_ = nil;
 
   // The current download task.
   std::unique_ptr<web::DownloadTask> download_task_;
+
+  // The preview that completed while the tab was hidden.
+  std::optional<PendingARPreview> pending_preview_;
+
+  base::ScopedObservation<web::WebState, web::WebStateObserver>
+      web_state_observation_{this};
 };
 
 #endif  // IOS_CHROME_BROWSER_DOWNLOAD_MODEL_AR_QUICK_LOOK_TAB_HELPER_H_
diff --git a/ios/chrome/browser/download/model/ar_quick_look_tab_helper.mm b/ios/chrome/browser/download/model/ar_quick_look_tab_helper.mm
index c5ae860..562c018 100644
--- a/ios/chrome/browser/download/model/ar_quick_look_tab_helper.mm
+++ b/ios/chrome/browser/download/model/ar_quick_look_tab_helper.mm
@@ -104,9 +104,12 @@
 
 }  // namespace
 
+#pragma mark - Initialization
+
 ARQuickLookTabHelper::ARQuickLookTabHelper(web::WebState* web_state)
     : web_state_(web_state) {
-  DCHECK(web_state_);
+  CHECK(web_state_);
+  web_state_observation_.Observe(web_state);
 }
 
 ARQuickLookTabHelper::~ARQuickLookTabHelper() {
@@ -115,6 +118,8 @@
   }
 }
 
+#pragma mark - Public
+
 void ARQuickLookTabHelper::Download(
     std::unique_ptr<web::DownloadTask> download_task) {
   DCHECK(download_task);
@@ -197,10 +202,14 @@
 
   NSURL* file_url =
       base::apple::FilePathToNSURL(download_task_->GetResponsePath());
-  [delegate_ presentUSDZFileWithURL:file_url
-                       canonicalURL:canonical_url
-                           webState:web_state_
-                allowContentScaling:allow_content_scaling];
+  if (web_state_->IsVisible()) {
+    [delegate_ presentUSDZFileWithURL:file_url
+                         canonicalURL:canonical_url
+                             webState:web_state_
+                  allowContentScaling:allow_content_scaling];
+  } else {
+    pending_preview_ = {file_url, canonical_url, allow_content_scaling};
+  }
 }
 
 void ARQuickLookTabHelper::RemoveCurrentDownload() {
@@ -208,6 +217,8 @@
   download_task_.reset();
 }
 
+#pragma mark - DownloadTaskObserver
+
 void ARQuickLookTabHelper::OnDownloadUpdated(web::DownloadTask* download_task) {

diff --git a/ios/chrome/browser/download/coordinator/safari_download_coordinator_unittest.mm b/ios/chrome/browser/download/coordinator/safari_download_coordinator_unittest.mm
index 70bdadf..e2c71c2 100644
--- a/ios/chrome/browser/download/coordinator/safari_download_coordinator_unittest.mm
+++ b/ios/chrome/browser/download/coordinator/safari_download_coordinator_unittest.mm
@@ -20,6 +20,7 @@
 #import "ios/chrome/browser/shared/model/web_state_list/web_state_list.h"
 #import "ios/chrome/browser/shared/model/web_state_list/web_state_opener.h"
 #import "ios/chrome/test/scoped_key_window.h"
+#import "ios/web/public/test/fakes/fake_download_task.h"
 #import "ios/web/public/test/fakes/fake_web_state.h"
 #import "ios/web/public/test/web_task_environment.h"
 #import "net/base/apple/url_conversions.h"
@@ -83,6 +84,7 @@
     // SafariDownloadTabHelper instances once started.
     auto web_state = std::make_unique<web::FakeWebState>();
     auto* web_state_ptr = web_state.get();
+    web_state_ptr->WasShown();
     SafariDownloadTabHelper::CreateForWebState(web_state_ptr);
     browser_->GetWebStateList()->InsertWebState(std::move(web_state));
     [coordinator_ start];
@@ -241,4 +243,33 @@
       0);
 }
 
+// Tests that SafariDownloadTabHelper defers UI alert presentation when the
+// WebState is hidden.
+TEST_F(SafariDownloadCoordinatorTest,
+       DeferSafariDownloadPresentationWhenHidden) {
+  web::FakeWebState* fake_web_state = static_cast<web::FakeWebState*>(
+      browser_->GetWebStateList()->GetWebStateAt(0));
+  fake_web_state->WasHidden();
+
+  auto task = std::make_unique<web::FakeDownloadTask>(
+      GURL("https://test.test/mobileconfig"), kMobileConfigurationType);
+
+  // Start the download in tab helper.
+  tab_helper()->DownloadMobileConfig(std::move(task));
+
+  // The warning alert should not be presented while hidden.
+  EXPECT_FALSE(WaitUntilConditionOrTimeout(kWaitForUIElementTimeout, ^{
+    return [base_view_controller_.presentedViewController class] ==
+           [UIAlertController class];
+  }));
+
+  // Now show the web state. The warning alert should be presented.
+  fake_web_state->WasShown();
+
+  EXPECT_TRUE(WaitUntilConditionOrTimeout(kWaitForUIElementTimeout, ^{
+    return [base_view_controller_.presentedViewController class] ==
+           [UIAlertController class];
+  }));
+}
+
 }  // namespace
diff --git a/ios/chrome/browser/download/model/ar_quick_look_tab_helper_unittest.mm b/ios/chrome/browser/download/model/ar_quick_look_tab_helper_unittest.mm
index a73abfa..44acc3e3 100644
--- a/ios/chrome/browser/download/model/ar_quick_look_tab_helper_unittest.mm
+++ b/ios/chrome/browser/download/model/ar_quick_look_tab_helper_unittest.mm
@@ -48,6 +48,7 @@
   ARQuickLookTabHelperTest()
       : delegate_([[FakeARQuickLookTabHelperDelegate alloc] init]) {
     ARQuickLookTabHelper::CreateForWebState(&web_state_);
+    web_state_.WasShown();
     ARQuickLookTabHelper::FromWebState(&web_state_)->set_delegate(delegate_);
   }
 
@@ -59,9 +60,10 @@
 
   base::HistogramTester* histogram_tester() { return &histogram_tester_; }
 
+  web::FakeWebState web_state_;
+
  private:
   web::WebTaskEnvironment task_environment_;
-  web::FakeWebState web_state_;
   FakeARQuickLookTabHelperDelegate* delegate_;
   base::HistogramTester histogram_tester_;
 };
@@ -546,6 +548,33 @@
       1);
 }
 
+// Tests deferring AR model preview when the tab is hidden.
+TEST_F(ARQuickLookTabHelperTest, DeferARPreviewWhenHidden) {
+  web_state_.WasHidden();
+
+  auto task = std::make_unique<web::FakeDownloadTask>(GURL(kUrl), "other");
+  task->SetGeneratedFileName(base::FilePath(kTestUsdzFileName));
+  web::FakeDownloadTask* task_ptr = task.get();
+
+  {
+    web::test::WaitDownloadTaskUpdated observer(task_ptr);
+    tab_helper()->Download(std::move(task));
+    observer.Wait();
+  }
+
+  task_ptr->SetDone(true);
+
+  // The delegate should not be notified while hidden.
+  EXPECT_EQ(0U, delegate().fileURLs.count);
+
+  // Now, show the web state. The delegate should be notified.
+  web_state_.WasShown();
+  EXPECT_EQ(1U, delegate().fileURLs.count);
+  EXPECT_TRUE([delegate().fileURLs.firstObject isKindOfClass:[NSURL class]]);
+  EXPECT_TRUE(delegate().allowsContentScaling);
+  EXPECT_FALSE(delegate().canonicalWebPageURL);
+}
+
 INSTANTIATE_TEST_SUITE_P(,
                          ARQuickLookTabHelperTest,
                          ::testing::Values(kUsdzMimeType,
diff --git a/ios/chrome/browser/download/model/pass_kit_tab_helper_unittest.mm b/ios/chrome/browser/download/model/pass_kit_tab_helper_unittest.mm
index dfbb379b8..a1f78e94 100644
--- a/ios/chrome/browser/download/model/pass_kit_tab_helper_unittest.mm
+++ b/ios/chrome/browser/download/model/pass_kit_tab_helper_unittest.mm
@@ -36,6 +36,7 @@
  protected:
   PassKitTabHelperTest() : handler_([[FakeWebContentHandler alloc] init]) {
     PassKitTabHelper::CreateForWebState(&web_state_);
+    web_state_.WasShown();
     PassKitTabHelper::FromWebState(&web_state_)
         ->SetWebContentsHandler(handler_);
   }
@@ -323,3 +324,38 @@
           DownloadPassKitResult::kUnauthorizedFailure),
       1);
 }
+
+// Tests deferring PassKit presentation when the tab is hidden.
+TEST_F(PassKitTabHelperTest, DeferPassKitPresentationWhenHidden) {
+  web_state_.WasHidden();
+
+  auto task =
+      std::make_unique<web::FakeDownloadTask>(GURL(kUrl), kPkPassMimeType);
+  web::FakeDownloadTask* task_ptr = task.get();
+  tab_helper()->Download(std::move(task));
+
+  std::string pass_data =
+      testing::GetTestFileContents(testing::kPkPassFilePath);
+  NSData* data = [NSData dataWithBytes:pass_data.data()
+                                length:pass_data.size()];
+  task_ptr->SetResponseData(data);
+  task_ptr->SetDone(true);
+
+  // The dialog should not be shown while the web state is hidden.
+  EXPECT_EQ(0U, handler_.passes.count);
+
+  // Show the web state. The dialog should be shown.
+  web_state_.WasShown();
+  EXPECT_EQ(1U, handler_.passes.count);
+  PKPass* pass = handler_.passes.firstObject;
+  EXPECT_TRUE([pass isKindOfClass:[PKPass class]]);
+  EXPECT_EQ(PKPassTypeBarcode, pass.passType);
+  EXPECT_NSEQ(@"pass.com.apple.devpubs.example", pass.passTypeIdentifier);
+  EXPECT_NSEQ(@"Toy Town", pass.organizationName);
+
+  histogram_tester_.ExpectUniqueSample(
+      kUmaDownloadPassKitResult,
+      static_cast<base::HistogramBase::Sample32>(
+          DownloadPassKitResult::kSuccessful),
+      1);
+}
diff --git a/ios/chrome/browser/download/model/vcard_tab_helper_unittest.mm b/ios/chrome/browser/download/model/vcard_tab_helper_unittest.mm
index 15d69dc0..e3fb624 100644
--- a/ios/chrome/browser/download/model/vcard_tab_helper_unittest.mm
+++ b/ios/chrome/browser/download/model/vcard_tab_helper_unittest.mm
@@ -27,7 +27,10 @@
 // Test fixture for testing VcardTabHelperTest class.
 class VcardTabHelperTest : public PlatformTest {
  protected:
-  VcardTabHelperTest() { VcardTabHelper::CreateForWebState(&web_state_); }
+  VcardTabHelperTest() {
+    VcardTabHelper::CreateForWebState(&web_state_);
+    web_state_.WasShown();
+  }
 
   VcardTabHelper* tab_helper() {
     return VcardTabHelper::FromWebState(&web_state_);
@@ -79,3 +82,37 @@
 
   EXPECT_OCMOCK_VERIFY(mockHandler);
 }
+
+// Tests deferring vcard presentation when the tab is hidden.
+TEST_F(VcardTabHelperTest, DeferVcardPresentationWhenHidden) {
+  web_state_.WasHidden();
+
+  auto task =
+      std::make_unique<web::FakeDownloadTask>(GURL(kUrl), kVcardMimeType);
+  web::FakeDownloadTask* task_ptr = task.get();
+  tab_helper()->Download(std::move(task));
+
+  std::string pass_data = testing::GetTestFileContents(testing::kVcardFilePath);
+  NSData* data = [NSData dataWithBytes:pass_data.data()
+                                length:pass_data.size()];
+
+  id mock_handler = OCMProtocolMock(@protocol(VcardTabHelperDelegate));
+  tab_helper()->set_delegate(mock_handler);
+
+  // The delegate should not be notified while the web state is hidden.
+  [[mock_handler reject] openVcardFromData:OCMOCK_ANY];
+
+  task_ptr->SetResponseData(data);
+  task_ptr->SetDone(true);
+
+  EXPECT_OCMOCK_VERIFY(mock_handler);
+
+  // Now, show the web state. The delegate should be called.
+  id mock_handler_visible = OCMProtocolMock(@protocol(VcardTabHelperDelegate));
+  tab_helper()->set_delegate(mock_handler_visible);
+  OCMExpect([mock_handler_visible openVcardFromData:data]);
+
+  web_state_.WasShown();
+
+  EXPECT_OCMOCK_VERIFY(mock_handler_visible);
+}