arc-a11y: Use correct scale factor for ARC R

Starting ARC R, ARC natively supports display density. As a result, when
the client is ARC P, the bounds are always scaled by the default device
scale factor, and when the client is ARC R and later, the bounds are
always scaled by the screen scale of the display, which matches the
browser behavior.

This CL addresses the above change in accessibility layer.

AX-Relnotes: n/a. (a part of preparation for ARC R)
Bug: b:17251157
Test: manual. Open PlayStore and change scale factor by ctrl+shift+(+/-) with P and R.
Change-Id: Iae39adaed7b3fc7a00962edc9da617b89dea7202
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2540266
Commit-Queue: Hiroki Sato <hirokisato@chromium.org>
Reviewed-by: David Tseng <dtseng@chromium.org>
Reviewed-by: Sara Kato <sarakato@chromium.org>
Cr-Commit-Position: refs/heads/master@{#829057}

chrome/browser/chromeos/arc/accessibility/accessibility_info_data_wrapper.cc

@@ -35,9 +35,9 @@ void AccessibilityInfoDataWrapper::PopulateBounds(
         tree_source_->is_input_method_window() || root->GetId() != GetId()) {
       // By default, populate the bounds relative to the tree root.
       const gfx::Rect& root_bounds = root->GetBounds();
-
       info_data_bounds.Offset(-1 * root_bounds.x(), -1 * root_bounds.y());
-      out_bounds = ToChromeScale(info_data_bounds);
+
+      out_bounds = ScaleAndroidPxToChromePx(info_data_bounds, window);
       out_data->relative_bounds.offset_container_id = root->GetId();
     } else {
       // For the root node of application tree, populate the bounds to be
@@ -46,17 +46,21 @@ void AccessibilityInfoDataWrapper::PopulateBounds(
       DCHECK(widget);
       DCHECK(widget->widget_delegate());
       DCHECK(widget->widget_delegate()->GetContentsView());
-      const gfx::Rect& root_bounds =
-          widget->widget_delegate()->GetContentsView()->GetBoundsInScreen();
+      gfx::PointF root_origin = gfx::PointF(widget->widget_delegate()
+                                                ->GetContentsView()
+                                                ->GetBoundsInScreen()
+                                                .origin());
 
-      out_bounds = ToChromeBounds(info_data_bounds, widget);
-      out_bounds.Offset(-1 * root_bounds.x(), -1 * root_bounds.y());
-    }
+      // Adjust the origin because a maximized window has an offset in Android.
+      root_origin.Offset(0, -1 * GetChromeWindowHeightOffsetInDip(window));
 
-    // |out_bounds| is in Chrome DPI here. As ARC is considered the same as web
-    // in Chrome automation, scale the bounds by device scale factor.
-    out_bounds.Scale(
+      // Scale to Chrome pixels.
+      root_origin.Scale(
           window->GetToplevelWindow()->layer()->device_scale_factor());
+
+      out_bounds = ScaleAndroidPxToChromePx(info_data_bounds, window);
+      out_bounds.Offset(-1 * root_origin.x(), -1 * root_origin.y());
+    }
   } else {
     // We cannot compute global bounds, so use the raw bounds.
     out_bounds.SetRect(info_data_bounds.x(), info_data_bounds.y(),

chrome/browser/chromeos/arc/accessibility/arc_accessibility_helper_bridge.cc

@@ -93,9 +93,14 @@ void DispatchFocusChange(arc::mojom::AccessibilityNodeInfoData* node_data,
   if (!active_window)
     return;
 
-  gfx::Rect bounds_in_screen = gfx::ToEnclosingRect(arc::ToChromeBounds(
+  // Convert bounds from Android pixels to Chrome DIP, and adjust coordinate to
+  // Chrome's screen coordinate.
+  gfx::Rect bounds_in_screen = gfx::ScaleToEnclosingRect(
       node_data->bounds_in_screen,
-      views::Widget::GetWidgetForNativeView(active_window)));
+      1.0f / exo::WMHelper::GetInstance()->GetDeviceScaleFactorForWindow(
+                 active_window));
+  bounds_in_screen.Offset(0,
+                          arc::GetChromeWindowHeightOffsetInDip(active_window));
 
   bool is_editable = arc::GetBooleanProperty(
       node_data, arc::mojom::AccessibilityBooleanProperty::EDITABLE);
@@ -677,8 +682,8 @@ ArcAccessibilityHelperBridge::OnGetTextLocationDataResultInternal(
   if (!active_window)
     return base::nullopt;
 
-  gfx::RectF rect_f = arc::ToChromeScale(*result_rect);
-  rect_f.Scale(DeviceScaleFactorFromWindow(active_window));
+  const gfx::RectF& rect_f =
+      ScaleAndroidPxToChromePx(result_rect.value(), active_window);
   return gfx::ToEnclosingRect(rect_f);
 }
 

chrome/browser/chromeos/arc/accessibility/geometry_util.cc

@@ -14,28 +14,32 @@
 #include "ui/views/widget/widget.h"
 
 namespace arc {
-gfx::RectF ToChromeScale(const gfx::Rect& bounds) {
+gfx::RectF ScaleAndroidPxToChromePx(const gfx::Rect& android_bounds,
+                                    aura::Window* window) {
   DCHECK(exo::WMHelper::HasInstance());
-  gfx::RectF bounds_f(bounds);
-  bounds_f.Scale(1.0f /
-                 exo::WMHelper::GetInstance()->GetDefaultDeviceScaleFactor());
-  return bounds_f;
-}
+  DCHECK(window);
 
-gfx::RectF ToChromeBounds(const gfx::Rect& bounds, views::Widget* widget) {
-  DCHECK(widget);
-  gfx::RectF chrome_bounds = ToChromeScale(bounds);
+  const float chrome_dsf =
+      window->GetToplevelWindow()->layer()->device_scale_factor();
+  const float android_dsf =
+      exo::WMHelper::GetInstance()->GetDeviceScaleFactorForWindow(window);
+  if (chrome_dsf == android_dsf)
+    return gfx::RectF(android_bounds);
 
+  gfx::RectF chrome_bounds(android_bounds);
+  chrome_bounds.Scale(chrome_dsf / android_dsf);
+  return chrome_bounds;
+}
+
+int GetChromeWindowHeightOffsetInDip(aura::Window* window) {
   // On Android side, content is rendered without considering height of
-  // caption bar, e.g. Content is rendered at y:0 instead of y:32 where 32 is
-  // height of caption bar. Add back height of caption bar here.
-  if (widget->IsMaximized()) {
-    chrome_bounds.Offset(
-        0,
-        widget->non_client_view()->frame_view()->GetBoundsForClientView().y());
-  }
+  // caption bar when it's maximized, e.g. Content is rendered at y:0 instead of
+  // y:32 where 32 is height of caption bar.
+  views::Widget* widget = views::Widget::GetWidgetForNativeView(window);
+  if (!widget->IsMaximized())
+    return 0;
 
-  return chrome_bounds;
+  return widget->non_client_view()->frame_view()->GetBoundsForClientView().y();
 }
 }  // namespace arc
 

chrome/browser/chromeos/arc/accessibility/geometry_util.h

@@ -11,18 +11,19 @@ namespace gfx {
 class RectF;
 }
 
-namespace views {
-class Widget;
+namespace aura {
+class Window;
 }
 
 namespace arc {
-// Given ARC pixels, returns DIPs in Chrome OS main display.
-// This function only scales the bounds.
-gfx::RectF ToChromeScale(const gfx::Rect& rect);
+// Given a rect in Android pixels, returns a scaled rectangle in Chrome pixels.
+// This only scales the given bounds.
+gfx::RectF ScaleAndroidPxToChromePx(const gfx::Rect& android_bounds,
+                                    aura::Window* window);
 
-// Given ARC pixels in screen coordinate, returns DIPs in Chrome OS main
-// display. This function adjusts differences between ARC and Chrome.
-gfx::RectF ToChromeBounds(const gfx::Rect& rect, views::Widget* widget);
+// Returns an difference of y coordinate in DIP between Android internal bounds
+// and what Chrome actually renders in the screen.
+int GetChromeWindowHeightOffsetInDip(aura::Window* window);
 }  // namespace arc
 
 #endif  // CHROME_BROWSER_CHROMEOS_ARC_ACCESSIBILITY_GEOMETRY_UTIL_H_