(Reland) top-chrome-slide: Disable the behavior when Chromevox is enabled.

Users of Chromevox may need to touch explore the webpage, and for
things to remain consistent, we should disable hiding top-chrome
with gesture scrolls as long as Chromevox is enabled.

R=sky@chromium.org
BUG=857331, 896514
TEST=Added a new browser test.

Reviewed-on: https://chromium-review.googlesource.com/c/1284289Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Ahmed Fakhry <afakhry@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#600408}
Change-Id: I388bc5056f956bea2edffc7127dcab533824e56b
Reviewed-on: https://chromium-review.googlesource.com/c/1287510
Cr-Commit-Position: refs/heads/master@{#600966}

chrome/browser/ui/views/frame/top_controls_slide_controller_chromeos.cc

@@ -37,6 +37,13 @@ bool IsTabletModeEnabled() {
          TabletModeClient::Get()->tablet_mode_enabled();
 }
 
+bool IsSpokenFeedbackEnabled() {
+  chromeos::AccessibilityManager* accessibility_manager =
+      chromeos::AccessibilityManager::Get();
+  return accessibility_manager &&
+         accessibility_manager->IsSpokenFeedbackEnabled();
+}
+
 // Based on the current status of |contents|, returns the browser top controls
 // shown state constraints, which specifies if the top controls are allowed to
 // be only shown, or either shown or hidden.
@@ -275,7 +282,16 @@ TopControlsSlideControllerChromeOS::TopControlsSlideControllerChromeOS(
 
   browser_view_->browser()->tab_strip_model()->AddObserver(this);
 
-  OnEnabledStateChanged(IsTabletModeEnabled() && !browser_view->IsFullscreen());
+  chromeos::AccessibilityManager* accessibility_manager =
+      chromeos::AccessibilityManager::Get();
+  if (accessibility_manager) {
+    accessibility_status_subscription_ =
+        accessibility_manager->RegisterCallback(base::BindRepeating(
+            &TopControlsSlideControllerChromeOS::OnAccessibilityStatusChanged,
+            base::Unretained(this)));
+  }
+
+  OnEnabledStateChanged(CanEnable(base::nullopt));
 }
 
 TopControlsSlideControllerChromeOS::~TopControlsSlideControllerChromeOS() {
@@ -342,14 +358,13 @@ void TopControlsSlideControllerChromeOS::SetShownRatio(
     defer_disabling_ = false;
 
     // Don't just set |is_enabled_| to false. Make sure it's a correct value.
-    OnEnabledStateChanged(IsTabletModeEnabled() &&
-                          !browser_view_->IsFullscreen());
+    OnEnabledStateChanged(CanEnable(base::nullopt));
   }
 }
 
 void TopControlsSlideControllerChromeOS::OnBrowserFullscreenStateWillChange(
     bool new_fullscreen_state) {
-  OnEnabledStateChanged(IsTabletModeEnabled() && !new_fullscreen_state);
+  OnEnabledStateChanged(CanEnable(new_fullscreen_state));
 }
 
 bool TopControlsSlideControllerChromeOS::DoBrowserControlsShrinkRendererSize(
@@ -391,7 +406,7 @@ bool TopControlsSlideControllerChromeOS::IsTopControlsGestureScrollInProgress()
 
 void TopControlsSlideControllerChromeOS::OnTabletModeToggled(
     bool tablet_mode_enabled) {
-  OnEnabledStateChanged(tablet_mode_enabled && !browser_view_->IsFullscreen());
+  OnEnabledStateChanged(CanEnable(base::nullopt));
 }
 
 void TopControlsSlideControllerChromeOS::TabInsertedAt(
@@ -477,6 +492,24 @@ void TopControlsSlideControllerChromeOS::Observe(
     UpdateBrowserControlsStateShown(active_contents, true /* animate */);
 }
 
+bool TopControlsSlideControllerChromeOS::CanEnable(
+    base::Optional<bool> fullscreen_state) const {
+  return IsTabletModeEnabled() &&
+         !(fullscreen_state ? *fullscreen_state
+                            : browser_view_->IsFullscreen()) &&
+         !IsSpokenFeedbackEnabled();
+}
+
+void TopControlsSlideControllerChromeOS::OnAccessibilityStatusChanged(
+    const chromeos::AccessibilityStatusEventDetails& event_details) {
+  if (event_details.notification_type !=
+      chromeos::ACCESSIBILITY_TOGGLE_SPOKEN_FEEDBACK) {
+    return;
+  }
+
+  OnEnabledStateChanged(CanEnable(base::nullopt));
+}
+
 void TopControlsSlideControllerChromeOS::OnEnabledStateChanged(bool new_state) {
   if (new_state == is_enabled_)
     return;

chrome/browser/ui/views/frame/top_controls_slide_controller_chromeos.h

@@ -9,6 +9,8 @@
 
 #include "base/containers/flat_map.h"
 #include "base/macros.h"
+#include "base/optional.h"
+#include "chrome/browser/chromeos/accessibility/accessibility_manager.h"
 #include "chrome/browser/ui/ash/tablet_mode_client_observer.h"
 #include "chrome/browser/ui/tabs/tab_strip_model_observer.h"
 #include "chrome/browser/ui/views/frame/top_controls_slide_controller.h"
@@ -82,6 +84,21 @@ class TopControlsSlideControllerChromeOS
                const content::NotificationDetails& details) override;
 
  private:
+  // Returns true if this feature can be turned on. If |fullscreen_state| is
+  // supplied, it will be used in calculating the result, otherwise the current
+  // fullscreen state will be queried from BrowserView. This is needed since
+  // BrowserView informs us with fullscreen state changes before they happen
+  // (See OnBrowserFullscreenStateWillChange()) so that we can disable the
+  // sliding behavior *before* immersive mode is entered.
+  bool CanEnable(base::Optional<bool> fullscreen_state) const;
+
+  // Called back from the AccessibilityManager so that we're updated by the
+  // status of Chromevox, which when enabled, sliding the top-controls should
+  // be disabled. This is important for users who want to touch explore and need
+  // this to be consistent.
+  void OnAccessibilityStatusChanged(
+      const chromeos::AccessibilityStatusEventDetails& event_details);
+
   void OnEnabledStateChanged(bool new_state);
 
   // Refreshes the status of the browser top controls.
@@ -148,6 +165,9 @@ class TopControlsSlideControllerChromeOS
 
   content::NotificationRegistrar registrar_;
 
+  std::unique_ptr<chromeos::AccessibilityStatusSubscription>
+      accessibility_status_subscription_;
+
   DISALLOW_COPY_AND_ASSIGN(TopControlsSlideControllerChromeOS);
 };
 

chrome/browser/ui/views/frame/top_controls_slide_controller_chromeos_browsertest.cc

@@ -18,6 +18,7 @@
 #include "base/strings/safe_sprintf.h"
 #include "base/test/scoped_feature_list.h"
 #include "cc/base/math_util.h"
+#include "chrome/browser/chromeos/accessibility/accessibility_manager.h"
 #include "chrome/browser/ui/ash/tablet_mode_client.h"
 #include "chrome/browser/ui/browser_commands.h"
 #include "chrome/browser/ui/views/bookmarks/bookmark_bar_view.h"
@@ -1008,4 +1009,78 @@ IN_PROC_BROWSER_TEST_F(TopControlsSlideControllerTest,
   CheckBrowserLayout(browser_view(), TopChromeShownState::kFullyShown);
 }
 
+// Waits for a compositor frame to be drawn and committed on the given
+// web_contents.
+class CompositorFrameWaiter : content::WebContentsObserver {
+ public:
+  explicit CompositorFrameWaiter(content::WebContents* contents)
+      : WebContentsObserver(contents) {}
+  ~CompositorFrameWaiter() override = default;
+
+  void Wait() { run_loop_.Run(); }
+
+  // content::WebContentsObserver:
+  void DidCommitAndDrawCompositorFrame() override { run_loop_.Quit(); }
+
+ private:
+  base::RunLoop run_loop_;
+
+  DISALLOW_COPY_AND_ASSIGN(CompositorFrameWaiter);
+};
+
+IN_PROC_BROWSER_TEST_F(TopControlsSlideControllerTest, TestToggleChromeVox) {
+  ToggleTabletMode();
+  ASSERT_TRUE(GetTabletModeEnabled());
+  EXPECT_TRUE(top_controls_slide_controller()->IsEnabled());
+  EXPECT_FLOAT_EQ(top_controls_slide_controller()->GetShownRatio(), 1.f);
+
+  OpenUrlAtIndex(embedded_test_server()->GetURL("/top_controls_scroll.html"),
+                 0);
+  content::WebContents* active_contents =
+      browser_view()->GetActiveWebContents();
+  PageStateUpdateWaiter page_state_update_waiter(active_contents);
+  page_state_update_waiter.Wait();
+  EXPECT_TRUE(
+      browser_view()->DoBrowserControlsShrinkRendererSize(active_contents));
+
+  aura::Window* browser_window = browser()->window()->GetNativeWindow();
+  ui::test::EventGenerator event_generator(browser_window->GetRootWindow(),
+                                           browser_window);
+  const gfx::Point start_point = event_generator.current_location();
+  const gfx::Point end_point = start_point + gfx::Vector2d(0, -100);
+  GenerateGestureFlingScrollSequence(&event_generator, start_point, end_point);
+  TopControlsShownRatioWaiter waiter(top_controls_slide_controller());
+  waiter.WaitForRatio(0.f);
+  EXPECT_FLOAT_EQ(top_controls_slide_controller()->GetShownRatio(), 0);
+  CheckBrowserLayout(browser_view(), TopChromeShownState::kFullyHidden);
+
+  // Enable Chromevox (spoken feedback) and expect that top-chrome will be fully
+  // shown, and sliding top-chrome is no longer enabled.
+  chromeos::AccessibilityManager::Get()->EnableSpokenFeedback(true);
+  EXPECT_TRUE(chromeos::AccessibilityManager::Get()->IsSpokenFeedbackEnabled());
+  waiter.WaitForRatio(1.f);
+  EXPECT_FLOAT_EQ(top_controls_slide_controller()->GetShownRatio(), 1.f);
+  EXPECT_FALSE(top_controls_slide_controller()->IsEnabled());
+  EXPECT_EQ(browser_view()->GetTopControlsHeight(), 0);
+  EXPECT_FALSE(
+      browser_view()->DoBrowserControlsShrinkRendererSize(active_contents));
+
+  // Now disable Chromevox, and expect it's now possible to hide top-chrome with
+  // gesture scrolling.
+  CompositorFrameWaiter compositor_frame_waiter(active_contents);
+  chromeos::AccessibilityManager::Get()->EnableSpokenFeedback(false);
+  compositor_frame_waiter.Wait();
+  EXPECT_FALSE(
+      chromeos::AccessibilityManager::Get()->IsSpokenFeedbackEnabled());
+  EXPECT_FLOAT_EQ(top_controls_slide_controller()->GetShownRatio(), 1.f);
+  EXPECT_TRUE(top_controls_slide_controller()->IsEnabled());
+  CheckBrowserLayout(browser_view(), TopChromeShownState::kFullyShown);
+  base::RunLoop().RunUntilIdle();
+  // Scroll down, top-chrome should hide.
+  GenerateGestureFlingScrollSequence(&event_generator, start_point, end_point);
+  waiter.WaitForRatio(0.f);
+  EXPECT_FLOAT_EQ(top_controls_slide_controller()->GetShownRatio(), 0);
+  CheckBrowserLayout(browser_view(), TopChromeShownState::kFullyHidden);
+}
+
 }  // namespace