Fix FlingController unittest failure

Currently, if experimental fling animation feature is turned on,
FlingControllerTest fails with an exception as
ScreenWin::GetPixelsPerInch() returns zero. As there is no display
instantiated while running FlingController unittest,
GetScreenWinDisplayNearestDIPPoint returns default ScreenWin object which
has zero value for pixels per inch.

This CL fixes the issue by return default value if the value of pixels
per inch from ScreenWinDisplay is zero.

Change-Id: I9cd7aa2ccfd62fa1896981f09a2dd4a336e49469
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1974620Reviewed-by: Robert Liao <robliao@chromium.org>
Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Reviewed-by: Daniel Libby <dlibby@microsoft.com>
Reviewed-by: David Bokan <bokan@chromium.org>
Commit-Queue: Robert Liao <robliao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#734692}

content/browser/renderer_host/input/fling_controller_unittest.cc

@@ -14,6 +14,10 @@
 #include "ui/events/base_event_utils.h"
 #include "ui/events/blink/fling_booster.h"
 
+#if defined(OS_WIN)
+#include "ui/display/win/test/scoped_screen_win.h"
+#endif
+
 using blink::WebGestureEvent;
 using blink::WebInputEvent;
 using blink::WebMouseWheelEvent;
@@ -172,6 +176,9 @@ class FlingControllerTest : public FlingControllerEventSenderClient,
   bool notified_client_after_fling_stop_ = false;
   bool first_wheel_event_sent_ = false;
   int sent_scroll_gesture_count_ = 0;
+#if defined(OS_WIN)
+  display::win::test::ScopedScreenWin scoped_screen_win_;
+#endif
 
  private:
   base::SimpleTestTickClock mock_clock_;

content/browser/renderer_host/input/fling_scheduler_unittest.cc

@@ -4,6 +4,7 @@
 
 #include "content/browser/renderer_host/input/fling_scheduler.h"
 
+#include "build/build_config.h"
 #include "content/public/test/browser_task_environment.h"
 #include "content/public/test/mock_render_process_host.h"
 #include "content/public/test/test_browser_context.h"
@@ -12,6 +13,10 @@
 #include "content/test/test_render_widget_host.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+#if defined(OS_WIN)
+#include "ui/display/win/test/scoped_screen_win.h"
+#endif
+
 namespace content {
 
 class FakeFlingScheduler : public FlingScheduler {
@@ -119,6 +124,9 @@ class FlingSchedulerTest : public testing::Test,
   MockRenderProcessHost* process_host_;
   TestRenderWidgetHostView* view_;
   std::unique_ptr<MockRenderWidgetHostDelegate> delegate_;
+#if defined(OS_WIN)
+  display::win::test::ScopedScreenWin scoped_screen_win_;
+#endif
 
   DISALLOW_COPY_AND_ASSIGN(FlingSchedulerTest);
 };

content/browser/renderer_host/input/gesture_event_queue_unittest.cc

@@ -18,6 +18,7 @@
 #include "base/test/task_environment.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
+#include "build/build_config.h"
 #include "content/browser/renderer_host/input/input_router_config_helper.h"
 #include "content/browser/renderer_host/input/touchpad_tap_suppression_controller.h"
 #include "content/common/input/synthetic_web_input_event_builders.h"
@@ -26,6 +27,10 @@
 #include "third_party/blink/public/common/input/web_input_event.h"
 #include "ui/events/blink/blink_features.h"
 
+#if defined(OS_WIN)
+#include "ui/display/win/test/scoped_screen_win.h"
+#endif
+
 using base::TimeDelta;
 using blink::WebGestureDevice;
 using blink::WebGestureEvent;
@@ -232,6 +237,9 @@ class GestureEventQueueTest : public testing::Test,
   std::unique_ptr<InputEventAckState> sync_ack_result_;
   std::unique_ptr<WebGestureEvent> sync_followup_event_;
   base::test::ScopedFeatureList feature_list_;
+#if defined(OS_WIN)
+  display::win::test::ScopedScreenWin scoped_screen_win_;
+#endif
 };
 
 // This is for tests that are to be run for all source devices.

content/browser/renderer_host/input/input_router_impl_unittest.cc

@@ -47,6 +47,10 @@
 #include "ui/events/event.h"
 #endif
 
+#if defined(OS_WIN)
+#include "ui/display/win/test/scoped_screen_win.h"
+#endif
+
 using blink::WebGestureDevice;
 using blink::WebGestureEvent;
 using blink::WebKeyboardEvent;
@@ -983,6 +987,10 @@ TEST_P(InputRouterImplTest, TouchTypesIgnoringAck) {
 #endif
 TEST_P(InputRouterImplTest, MAYBE_GestureTypesIgnoringAck) {
   // We test every gesture type, ensuring that the stream of gestures is valid.
+
+#if defined(OS_WIN)
+  display::win::test::ScopedScreenWin scoped_screen_win_;
+#endif
   const WebInputEvent::Type eventTypes[] = {
       WebInputEvent::kGestureTapDown,     WebInputEvent::kGestureShowPress,
       WebInputEvent::kGestureTapCancel,   WebInputEvent::kGestureScrollBegin,

content/browser/renderer_host/render_widget_host_view_aura_unittest.cc

@@ -122,6 +122,10 @@
 #include "ui/base/ime/input_method.h"
 #endif
 
+#if defined(OS_WIN)
+#include "ui/display/win/test/scoped_screen_win.h"
+#endif
+
 using testing::_;
 
 using blink::WebGestureEvent;
@@ -3668,6 +3672,11 @@ TEST_F(RenderWidgetHostViewAuraOverscrollTest,
        ScrollEventsOverscrollWithFling) {
   SetUpOverscrollEnvironment();
 
+#if defined(OS_WIN)
+  // Create a ScopedScreenWin.
+  display::win::test::ScopedScreenWin scoped_screen_win;
+#endif
+
   // Send a wheel event. ACK the event as not processed. This should not
   // initiate an overscroll gesture since it doesn't cross the threshold yet.
   SimulateWheelEvent(10, 0, 0, true, WebMouseWheelEvent::kPhaseBegan);
@@ -3743,6 +3752,11 @@ TEST_F(RenderWidgetHostViewAuraOverscrollTest,
        ScrollEventsOverscrollWithZeroFling) {
   SetUpOverscrollEnvironment();
 
+#if defined(OS_WIN)
+  // Create a ScopedScreenWin.
+  display::win::test::ScopedScreenWin scoped_screen_win;
+#endif
+
   // Send a wheel event. ACK the event as not processed. This should not
   // initiate an overscroll gesture since it doesn't cross the threshold yet.
   SimulateWheelEvent(10, 0, 0, true, WebMouseWheelEvent::kPhaseBegan);
@@ -3820,6 +3834,11 @@ TEST_F(RenderWidgetHostViewAuraOverscrollTest,
        MAYBE_ReverseFlingCancelsOverscroll) {
   SetUpOverscrollEnvironment();
 
+#if defined(OS_WIN)
+  // Create a ScopedScreenWin.
+  display::win::test::ScopedScreenWin scoped_screen_win;
+#endif
+
   {
     PressAndSetTouchActionAuto();
     // Start and end a gesture in the same direction without processing the
@@ -4672,6 +4691,11 @@ TEST_F(RenderWidgetHostViewAuraOverscrollTest,
        OverscrollStateResetsAfterScroll) {
   SetUpOverscrollEnvironment();
 
+#if defined(OS_WIN)
+  // Create a ScopedScreenWin.
+  display::win::test::ScopedScreenWin scoped_screen_win;
+#endif
+
   SimulateWheelEvent(0, 5, 0, true,
                      WebMouseWheelEvent::kPhaseBegan);  // sent directly
   SimulateWheelEvent(0, 30, 0, true,
@@ -5051,6 +5075,11 @@ TEST_F(RenderWidgetHostViewAuraTest, CorrectNumberOfAcksAreDispatched) {
 TEST_F(RenderWidgetHostViewAuraOverscrollTest, ScrollDeltasResetOnEnd) {
   SetUpOverscrollEnvironment();
 
+#if defined(OS_WIN)
+  // Create a ScopedScreenWin.
+  display::win::test::ScopedScreenWin scoped_screen_win;
+#endif
+
   PressAndSetTouchActionAuto();
   // Wheel event scroll ending with mouse move.
   SimulateWheelEvent(-30, -10, 0, true,

ui/display/BUILD.gn

@@ -145,6 +145,8 @@ jumbo_static_library("test_support") {
 
   if (is_win) {
     sources += [
+      "win/test/scoped_screen_win.cc",
+      "win/test/scoped_screen_win.h",
       "win/test/screen_util_win.cc",
       "win/test/screen_util_win.h",
     ]

ui/display/win/test/scoped_screen_win.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 "ui/display/win/test/scoped_screen_win.h"
+#include "ui/display/win/display_info.h"
+#include "ui/display/win/test/screen_util_win.h"
+
+namespace display {
+namespace win {
+namespace test {
+
+ScopedScreenWin::ScopedScreenWin() : ScreenWin(false) {
+  const gfx::Rect pixel_bounds = gfx::Rect(0, 0, 1920, 1200);
+  const gfx::Rect pixel_work = gfx::Rect(0, 0, 1920, 1100);
+  MONITORINFOEX monitor_info =
+      CreateMonitorInfo(pixel_bounds, pixel_work, L"primary");
+  std::vector<DisplayInfo> display_infos;
+  display_infos.push_back(
+      DisplayInfo(monitor_info, 1.0f /* device_scale_factor*/, 1.0f,
+                  Display::ROTATE_0, 60, gfx::Vector2dF(96.0, 96.0)));
+  UpdateFromDisplayInfos(display_infos);
+  previous_screen_ = Screen::GetScreen();
+  Screen::SetScreenInstance(this);
+}
+
+ScopedScreenWin::~ScopedScreenWin() {
+  Screen::SetScreenInstance(previous_screen_);
+}
+
+}  // namespace test
+}  // namespace win
+}  // namespace display

ui/display/win/test/scoped_screen_win.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 UI_DISPLAY_WIN_TEST_SCOPED_SCREEN_WIN_H_
+#define UI_DISPLAY_WIN_TEST_SCOPED_SCREEN_WIN_H_
+
+#include "base/macros.h"
+#include "ui/display/win/screen_win.h"
+
+namespace display {
+namespace win {
+namespace test {
+
+// ScopedScreenWin construct a instance of ScreenWinDisplay with bounds
+// (1920,1080). This will allow unittests to query the details about ScreenWin
+// using static methods. ScopedScreenWin needs to be initialized before running
+// the code that queries ScreenWin.
+class ScopedScreenWin : public ScreenWin {
+ public:
+  ScopedScreenWin();
+  ~ScopedScreenWin() override;
+
+ private:
+  Screen* previous_screen_;
+  DISALLOW_COPY_AND_ASSIGN(ScopedScreenWin);
+};
+
+}  // namespace test
+}  // namespace win
+}  // namespace display
+
+#endif  // UI_DISPLAY_WIN_TEST_SCOPED_SCREEN_WIN_H_