Create new accessibilityPrivate method to update magnifier viewport

Parent Tracking Bug: 1131153

Fixed: 1129711
AX-Relnotes: Add accessibilityPrivate method to update magnifier viewport and focus following highlight
Change-Id: Id5fa2c05e39f763b7a599e3445f40945a71f5e42
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2417457Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: David Tseng <dtseng@chromium.org>
Reviewed-by: Akihiro Ota <akihiroota@chromium.org>
Commit-Queue: Josiah Krutz <josiahk@google.com>
Cr-Commit-Position: refs/heads/master@{#812228}

ash/magnifier/magnification_controller.cc

@@ -266,6 +266,16 @@ void MagnificationController::HandleFocusedNodeChanged(
   MoveMagnifierWindowFollowRect(node_bounds_in_root);
 }
 
+void MagnificationController::HandleMoveMagnifierToRect(
+    const gfx::Rect& rect_in_screen) {
+  gfx::Rect node_bounds_in_root = rect_in_screen;
+  ::wm::ConvertRectFromScreen(root_window_, &node_bounds_in_root);
+  if (GetViewportRect().Contains(node_bounds_in_root))
+    return;
+
+  MoveMagnifierWindowFollowRect(node_bounds_in_root);
+}
+
 void MagnificationController::SwitchTargetRootWindow(
     aura::Window* new_root_window,
     bool redraw_original_root_window) {

ash/magnifier/magnification_controller.h

@@ -109,6 +109,15 @@ class ASH_EXPORT MagnificationController : public ui::EventHandler,
   void HandleFocusedNodeChanged(bool is_editable_node,
                                 const gfx::Rect& node_bounds_in_screen);
 
+  // Move |rect_in_screen| within the magnifier viewport. If |rect_in_screen| is
+  // already completely within the viewport, do nothing. If any edge of
+  // |rect_in_screen| is outside the viewport (e.g. if rect is larger than or
+  // extends partially beyond the viewport), center the overflowing dimensions
+  // of the viewport on center of |rect_in_screen| (e.g. center viewport
+  // vertically if |rect| extends beyond bottom of screen). Called from
+  // Accessibility Common extension. Called from Accessibility Common extension.
+  void HandleMoveMagnifierToRect(const gfx::Rect& rect_in_screen);
+
   // Switch the magnified root window to |new_root_window|. This does following:
   //  - Unzoom the current root_window.
   //  - Zoom the given new root_window |new_root_window|.

chrome/browser/accessibility/accessibility_extension_api.cc

@@ -14,6 +14,7 @@
 #include "base/strings/string_number_conversions.h"
 #include "base/values.h"
 #include "build/build_config.h"
+#include "chrome/browser/chromeos/accessibility/magnification_manager.h"
 #include "chrome/browser/extensions/api/tabs/tabs_constants.h"
 #include "chrome/browser/extensions/chrome_extension_function_details.h"
 #include "chrome/browser/extensions/extension_service.h"
@@ -409,6 +410,22 @@ AccessibilityPrivateHandleScrollableBoundsForPointFoundFunction::Run() {
   return RespondNow(NoArguments());
 }
 
+ExtensionFunction::ResponseAction
+AccessibilityPrivateMoveMagnifierToRectFunction::Run() {
+  std::unique_ptr<accessibility_private::MoveMagnifierToRect::Params> params =
+      accessibility_private::MoveMagnifierToRect::Params::Create(*args_);
+  EXTENSION_FUNCTION_VALIDATE(params);
+  accessibility_private::ScreenRect rect = std::move(params->rect);
+  gfx::Rect bounds(rect.left, rect.top, rect.width, rect.height);
+
+  chromeos::MagnificationManager* magnification_manager =
+      chromeos::MagnificationManager::Get();
+  if (magnification_manager)
+    magnification_manager->HandleMoveMagnifierToRectIfEnabled(bounds);
+
+  return RespondNow(NoArguments());
+}
+
 ExtensionFunction::ResponseAction
 AccessibilityPrivateToggleDictationFunction::Run() {
   ash::DictationToggleSource source = ash::DictationToggleSource::kChromevox;

chrome/browser/accessibility/accessibility_extension_api.h

@@ -120,6 +120,16 @@ class AccessibilityPrivateHandleScrollableBoundsForPointFoundFunction
       ACCESSIBILITY_PRIVATE_HANDLESCROLLABLEBOUNDSFORPOINTFOUND)
 };
 
+// API function that is called by the Accessibility Common extension to center
+// the magnifier viewport on a passed-in rect.
+class AccessibilityPrivateMoveMagnifierToRectFunction
+    : public ExtensionFunction {
+  ~AccessibilityPrivateMoveMagnifierToRectFunction() override {}
+  ResponseAction Run() override;
+  DECLARE_EXTENSION_FUNCTION("accessibilityPrivate.moveMagnifierToRect",
+                             ACCESSIBILITY_PRIVATE_MOVEMAGNIFIERTORECT)
+};
+
 // API function that is called when a user toggles Dictation from another
 // acessibility feature.
 class AccessibilityPrivateToggleDictationFunction : public ExtensionFunction {

chrome/browser/chromeos/accessibility/magnification_manager.cc

@@ -108,6 +108,19 @@ void MagnificationManager::HandleFocusedRectChangedIfEnabled(
   HandleFocusChanged(bounds_in_screen, is_editable);
 }
 
+void MagnificationManager::HandleMoveMagnifierToRectIfEnabled(
+    const gfx::Rect& rect) {
+  // Fullscreen magnifier and docked magnifier are mutually exclusive.
+  if (fullscreen_magnifier_enabled_) {
+    ash::Shell::Get()->magnification_controller()->HandleMoveMagnifierToRect(
+        rect);
+    return;
+  }
+  if (IsDockedMagnifierEnabled()) {
+    ash::DockedMagnifierController::Get()->CenterOnPoint(rect.CenterPoint());
+  }
+}
+
 void MagnificationManager::OnViewEvent(views::View* view,
                                        ax::mojom::Event event_type) {
   if (!fullscreen_magnifier_enabled_ && !IsDockedMagnifierEnabled())

chrome/browser/chromeos/accessibility/magnification_manager.h

@@ -68,6 +68,9 @@ class MagnificationManager
   void HandleFocusedRectChangedIfEnabled(const gfx::Rect& bounds_in_screen,
                                          bool is_editable);
 
+  // Move magnifier to ensure rect is within viewport if a magnifier is enabled.
+  void HandleMoveMagnifierToRectIfEnabled(const gfx::Rect& rect);
+
   // ProfileObserver:
   void OnProfileWillBeDestroyed(Profile* profile) override;
 

chrome/common/extensions/api/accessibility_private.json

@@ -407,6 +407,19 @@
         ],
         "platforms": ["chromeos"]
       },
+      {
+        "name": "moveMagnifierToRect",
+        "type": "function",
+        "description": "Called by the Accessibility Common extension to move |rect| within the magnifier viewport (e.g. when focus has changed). If |rect| is already completely within the viewport, magnifier doesn't move. If any edge of |rect| is outside the viewport (e.g. if rect is larger than or extends partially beyond the viewport), magnifier will center the overflowing dimensions of the viewport on center of |rect| (e.g. center viewport vertically if |rect| extends beyond bottom of screen).",
+        "parameters": [
+          {
+            "name": "rect",
+            "$ref": "ScreenRect",
+            "description": "Rect to ensure visible in the magnified viewport."
+          }
+        ],
+        "platforms": ["chromeos"]
+      },
       {
         "name": "toggleDictation",
         "type": "function",

extensions/browser/extension_function_histogram_value.h

@@ -1570,6 +1570,7 @@ enum HistogramValue {
   ACCESSIBILITY_PRIVATE_PERFORMACCELERATORACTION = 1507,
   DECLARATIVENETREQUEST_ISREGEXSUPPORTED = 1508,
   PASSWORDSPRIVATE_GETWEAKCREDENTIALS = 1509,
+  ACCESSIBILITY_PRIVATE_MOVEMAGNIFIERTORECT = 1510,
   // Last entry: Add new entries above, then run:
   // python tools/metrics/histograms/update_extension_histograms.py
   ENUM_BOUNDARY

third_party/closure_compiler/externs/accessibility_private.js

@@ -314,6 +314,14 @@ chrome.accessibilityPrivate.setSelectToSpeakState = function(state) {};
  */
 chrome.accessibilityPrivate.handleScrollableBoundsForPointFound = function(rect) {};
 
+/**
+ * Called by the Accessibility Common extension to update the magnifier viewport
+ * (e.g. when focus has changed).
+ * @param {!chrome.accessibilityPrivate.ScreenRect} rect Rect to ensure visible
+ *     in the magnified viewport.
+ */
+chrome.accessibilityPrivate.moveMagnifierToRect = function(rect) {};
+
 /**
  * Toggles dictation between active and inactive states.
  */

tools/metrics/histograms/enums.xml

@@ -24634,6 +24634,7 @@ Called by update_extension_histograms.py.-->
   <int value="1507" label="ACCESSIBILITY_PRIVATE_PERFORMACCELERATORACTION"/>
   <int value="1508" label="DECLARATIVENETREQUEST_ISREGEXSUPPORTED"/>
   <int value="1509" label="PASSWORDSPRIVATE_GETWEAKCREDENTIALS"/>
+  <int value="1510" label="ACCESSIBILITY_PRIVATE_MOVEMAGNIFIERTORECT"/>
 </enum>
 
 <enum name="ExtensionIconState">