WebShare: Add fake DataTransferManagerInterop for testing

Adding a class to represent the Windows DataTransferManagerInterop APIs
within tests, as well as basic unit tests to validate the test class
behaviors.

Bug: 1035527
Change-Id: I926078f3b54b350c622adb40fc84fe3614fa89d7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2397315
Commit-Queue: Hoch Hochkeppel <mhochk@microsoft.com>
Reviewed-by: Eric Willigers <ericwilligers@chromium.org>
Cr-Commit-Position: refs/heads/master@{#805564}

chrome/browser/webshare/win/fake_data_transfer_manager_interop.cc

+// Copyright 2020 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.
+
+#include "chrome/browser/webshare/win/fake_data_transfer_manager_interop.h"
+
+#include "base/bind_helpers.h"
+#include "base/callback.h"
+#include "base/task/post_task.h"
+#include "chrome/browser/webshare/win/fake_data_transfer_manager.h"
+#include "content/public/browser/browser_task_traits.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace webshare {
+
+FakeDataTransferManagerInterop::FakeDataTransferManagerInterop() = default;
+
+FakeDataTransferManagerInterop::~FakeDataTransferManagerInterop() {
+  // Though it is legal for consuming code to hold on to a DataTransferManager
+  // after releasing all references to the DataTransferManagerInterop, in a
+  // test environment the DataTransferManagerInterop is only expected to be
+  // torn down as part of the test cleanup, at which point the
+  // DataTransferManager references should also have been cleaned up.
+  for (auto& manager : managers_)
+    EXPECT_EQ(0u, manager.second.Reset());
+}
+
+IFACEMETHODIMP
+FakeDataTransferManagerInterop::GetForWindow(HWND app_window,
+                                             REFIID riid,
+                                             void** data_transfer_manager) {
+  auto it = managers_.find(app_window);
+  if (it != managers_.end()) {
+    *data_transfer_manager = it->second.Get();
+    it->second->AddRef();
+  } else {
+    auto mock = Microsoft::WRL::Make<FakeDataTransferManager>();
+    managers_.insert({app_window, mock});
+    *data_transfer_manager = mock.Get();
+    mock->AddRef();
+  }
+  return S_OK;
+}
+
+IFACEMETHODIMP FakeDataTransferManagerInterop::ShowShareUIForWindow(
+    HWND app_window) {
+  auto it = managers_.find(app_window);
+  if (it == managers_.end()) {
+    ADD_FAILURE() << "ShowShareUIForWindow called for HWND with no "
+                     "DataTransferManager (or DataRequested handler) defined.";
+    return E_FAIL;
+  }
+  switch (show_share_ui_for_window_behavior_) {
+    case ShowShareUIForWindowBehavior::FailImmediately:
+      return E_FAIL;
+    case ShowShareUIForWindowBehavior::InvokeEventSynchronously:
+      std::move(it->second->GetDataRequestedInvoker()).Run();
+      return S_OK;
+    case ShowShareUIForWindowBehavior::InvokeEventSynchronouslyAndReturnFailure:
+      std::move(it->second->GetDataRequestedInvoker()).Run();
+      return E_FAIL;
+    case ShowShareUIForWindowBehavior::ScheduleEvent:
+      EXPECT_TRUE(base::PostTask(FROM_HERE, {content::BrowserThread::UI},
+                                 it->second->GetDataRequestedInvoker()));
+      return S_OK;
+    case ShowShareUIForWindowBehavior::SucceedWithoutAction:
+      return S_OK;
+  }
+  NOTREACHED();
+  return E_UNEXPECTED;
+}
+
+base::OnceClosure FakeDataTransferManagerInterop::GetDataRequestedInvoker(
+    HWND app_window) {
+  auto it = managers_.find(app_window);
+  if (it == managers_.end()) {
+    ADD_FAILURE() << "GetDataRequestedInvoker called when no DataRequested "
+                     "event handler has been registered";
+    return base::DoNothing();
+  }
+  return it->second->GetDataRequestedInvoker();
+}
+
+bool FakeDataTransferManagerInterop::HasDataRequestedListener(HWND app_window) {
+  auto it = managers_.find(app_window);
+  if (it == managers_.end())
+    return false;
+  return it->second->HasDataRequestedListener();
+}
+
+void FakeDataTransferManagerInterop::SetShowShareUIForWindowBehavior(
+    ShowShareUIForWindowBehavior behavior) {
+  show_share_ui_for_window_behavior_ = behavior;
+}
+
+}  // namespace webshare

chrome/browser/webshare/win/fake_data_transfer_manager_interop.h

+// Copyright 2020 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.
+
+#ifndef CHROME_BROWSER_WEBSHARE_WIN_FAKE_DATA_TRANSFER_MANAGER_INTEROP_H_
+#define CHROME_BROWSER_WEBSHARE_WIN_FAKE_DATA_TRANSFER_MANAGER_INTEROP_H_
+
+#include <shlobj.h>
+#include <wrl/implements.h>
+#include <map>
+
+#include "base/callback_forward.h"
+
+namespace webshare {
+
+class FakeDataTransferManager;
+
+// Provides an implementation of IDataTransferManagerInterop for use in GTests.
+//
+// Like the Windows implementation, this class cloaks its implementation of
+// IDataTransferManagerInterop to closely match casting behaviors.
+class FakeDataTransferManagerInterop
+    : public Microsoft::WRL::RuntimeClass<
+          Microsoft::WRL::RuntimeClassFlags<
+              Microsoft::WRL::RuntimeClassType::WinRtClassicComMix>,
+          Microsoft::WRL::CloakedIid<IDataTransferManagerInterop>> {
+ public:
+  // Behavior options for the ShowShareUIForWindow API
+  enum ShowShareUIForWindowBehavior {
+    // Returns a failed value without invoking/scheduling the DataRequested
+    // event/handler.
+    FailImmediately,
+    // Invokes the DataRequested event/handler synchronously as part of the
+    // original invoking call. This matches the behavior exposed by Windows
+    // under various edge-case scenarios.
+    InvokeEventSynchronously,
+    // Invokes the DataRequested event/handler synchronously as part of the
+    // original invoking call, but then returns a failure result.
+    InvokeEventSynchronouslyAndReturnFailure,
+    // Schedules the invocation of the DataRequested event/handler to happen
+    // automatically, outside of the original invoking call. This matches the
+    // the most common behavior exposed by Windows.
+    ScheduleEvent,
+    // Returns a success value without invoking/scheduling the DataRequested
+    // event/handler. To later invoke the DataRequested event/handler, see
+    // |GetDataRequestedInvoker|.
+    SucceedWithoutAction
+  };
+
+  FakeDataTransferManagerInterop();
+  FakeDataTransferManagerInterop(const FakeDataTransferManagerInterop&) =
+      delete;
+  FakeDataTransferManagerInterop& operator=(
+      const FakeDataTransferManagerInterop&) = delete;
+  ~FakeDataTransferManagerInterop() override;
+
+  // IDataTransferManagerInterop:
+  IFACEMETHODIMP GetForWindow(HWND app_window,
+                              REFIID riid,
+                              void** data_transfer_manager) override;
+  IFACEMETHODIMP ShowShareUIForWindow(HWND app_window) override;
+
+  // Returns a callback that captures a reference to the current DataRequested
+  // event handler and, when invoked, triggers that handler.
+  //
+  // If the registered handler changes after this method is called the callback
+  // will still trigger the previous event handler, not a newly registered one.
+  base::OnceClosure GetDataRequestedInvoker(HWND app_window);
+
+  // Checks if there are any listeners registered for the DataRequested event
+  // on the given |app_window|.
+  bool HasDataRequestedListener(HWND app_window);
+
+  void SetShowShareUIForWindowBehavior(ShowShareUIForWindowBehavior behavior);
+
+ private:
+  ShowShareUIForWindowBehavior show_share_ui_for_window_behavior_ =
+      ShowShareUIForWindowBehavior::ScheduleEvent;
+  std::map<HWND, Microsoft::WRL::ComPtr<FakeDataTransferManager>> managers_;
+};
+
+}  // namespace webshare
+
+#endif  // CHROME_BROWSER_WEBSHARE_WIN_FAKE_DATA_TRANSFER_MANAGER_INTEROP_H_

chrome/test/BUILD.gn

@@ -299,6 +299,8 @@ static_library("test_support") {
     sources += [
       "../browser/webshare/win/fake_data_transfer_manager.cc",
       "../browser/webshare/win/fake_data_transfer_manager.h",
+      "../browser/webshare/win/fake_data_transfer_manager_interop.cc",
+      "../browser/webshare/win/fake_data_transfer_manager_interop.h",
       "//chrome/app/chrome_crash_reporter_client_win.cc",
     ]
     public_deps += [
@@ -5552,6 +5554,7 @@ test("unit_tests") {
       "../browser/notifications/win/notification_image_retainer_unittest.cc",
       "../browser/notifications/win/notification_template_builder_unittest.cc",
       "../browser/ui/views/uninstall_view_unittest.cc",
+      "../browser/webshare/win/fake_data_transfer_manager_interop_unittest.cc",
       "../browser/webshare/win/fake_data_transfer_manager_unittest.cc",
     ]
     deps += [