Fix shaking movement while navigating the Chrome menu in docked magnifier

Fixed: 1111074
AX-Relnotes: Fix shaking movement while navigating the Chrome menu in docked magnifier
Change-Id: Icdae63357af284fcce68f4a5d73c26fac7f6628a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2418012
Commit-Queue: Josiah Krutz <josiahk@google.com>
Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Reviewed-by: David Tseng <dtseng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#812950}

ash/magnifier/magnification_controller.cc

@@ -61,8 +61,8 @@ constexpr int kDefaultAnimationDurationInMs = 100;
 constexpr gfx::Tween::Type kCenterCaretAnimationTweenType = gfx::Tween::LINEAR;
 
 // The delay of the timer for moving magnifier window for centering the text
-// input focus.
-constexpr int kMoveMagnifierDelayInMs = 10;
+// input focus. Keep under one frame length (~16ms at 60hz).
+constexpr int kMoveMagnifierDelayInMs = 15;
 
 // Threshold of panning. If the cursor moves to within pixels (in DIP) of
 // |kCursorPanningMargin| from the edge, the view-port moves.

chrome/browser/chromeos/accessibility/magnification_manager.cc

@@ -30,7 +30,14 @@
 namespace chromeos {
 
 namespace {
+
+// The duration of time to ignore focus changes after the last mouse event.
+// Keep under one frame length (~16ms at 60hz).
+constexpr base::TimeDelta kTimeIgnoreFocusChangeAfterMouseEvent =
+    base::TimeDelta::FromMilliseconds(15);
+
 MagnificationManager* g_magnification_manager = nullptr;
+
 }  // namespace
 
 // static
@@ -121,6 +128,10 @@ void MagnificationManager::HandleMoveMagnifierToRectIfEnabled(
   }
 }
 
+void MagnificationManager::OnMouseEvent(ui::MouseEvent* event) {
+  last_mouse_event_ = base::TimeTicks::Now();
+}
+
 void MagnificationManager::OnViewEvent(views::View* view,
                                        ax::mojom::Event event_type) {
   if (!fullscreen_magnifier_enabled_ && !IsDockedMagnifierEnabled())
@@ -334,6 +345,12 @@ void MagnificationManager::HandleFocusChanged(const gfx::Rect& bounds_in_screen,
   if (bounds_in_screen.IsEmpty())
     return;
 
+  // Ignore focus changes while mouse activity is occurring.
+  if (base::TimeTicks::Now() - last_mouse_event_ <
+      kTimeIgnoreFocusChangeAfterMouseEvent) {
+    return;
+  }
+
   // Fullscreen magnifier and docked magnifier are mutually exclusive.
   if (fullscreen_magnifier_enabled_) {
     ash::Shell::Get()->magnification_controller()->HandleFocusedNodeChanged(

chrome/browser/chromeos/accessibility/magnification_manager.h

@@ -13,6 +13,7 @@
 #include "components/user_manager/user_manager.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
+#include "ui/events/event_handler.h"
 #include "ui/views/accessibility/ax_event_observer.h"
 
 class PrefChangeRegistrar;
@@ -35,6 +36,7 @@ class MagnificationManager
     : public content::NotificationObserver,
       public user_manager::UserManager::UserSessionStateObserver,
       public ProfileObserver,
+      public ui::EventHandler,
       public views::AXEventObserver {
  public:
   // Creates an instance of MagnificationManager. This should be called once.
@@ -74,6 +76,9 @@ class MagnificationManager
   // ProfileObserver:
   void OnProfileWillBeDestroyed(Profile* profile) override;
 
+  // ui::EventHandler overrides:
+  void OnMouseEvent(ui::MouseEvent* event) override;
+
   // views::AXEventObserver:
   void OnViewEvent(views::View* view, ax::mojom::Event event_type) override;
 
@@ -109,6 +114,10 @@ class MagnificationManager
   Profile* profile_ = nullptr;
   ScopedObserver<Profile, ProfileObserver> profile_observer_{this};
 
+  // Last mouse event time - used for ignoring focus changes for a few
+  // milliseconds after the last mouse event.
+  base::TimeTicks last_mouse_event_;
+
   bool fullscreen_magnifier_enabled_ = false;
   bool keep_focus_centered_ = false;
   double scale_ = 0.0;

chrome/browser/chromeos/chrome_browser_main_chromeos.cc

@@ -1049,6 +1049,10 @@ void ChromeBrowserMainPartsChromeos::PostBrowserStart() {
   if (system::InputDeviceSettings::Get()->ForceKeyboardDrivenUINavigation())
     event_rewriter_controller->SetKeyboardDrivenEventRewriterEnabled(true);
 
+  // Add MagnificationManager as a pretarget handler after ash:Shell is
+  // initialized.
+  ash::Shell::Get()->AddPreTargetHandler(MagnificationManager::Get());
+
   // In classic ash must occur after ash::Shell is initialized. Triggers a
   // fetch of the initial CrosSettings DeviceRebootOnShutdown policy.
   shutdown_policy_forwarder_ = std::make_unique<ShutdownPolicyForwarder>();
@@ -1116,6 +1120,8 @@ void ChromeBrowserMainPartsChromeos::PostMainMessageLoopRun() {
 
   assistant_state_client_.reset();
 
+  ash::Shell::Get()->RemovePreTargetHandler(MagnificationManager::Get());
+
   // Unregister CrosSettings observers before CrosSettings is destroyed.
   shutdown_policy_forwarder_.reset();