Support accessibility actions to increment / decrement sliders.

BUG=378799

Review URL: https://codereview.chromium.org/734933002

Cr-Commit-Position: refs/heads/master@{#304858}

10 files changed, 110 insertions, 25 deletions

diff --git a/content/browser/accessibility/browser_accessibility_android.cc b/content/browser/accessibility/browser_accessibility_android.cc
index 4ab0e6e..b80334f 100644
--- a/content/browser/accessibility/browser_accessibility_android.cc
+++ b/content/browser/accessibility/browser_accessibility_android.cc
@@ -92,6 +92,24 @@ bool BrowserAccessibilityAndroid::PlatformIsLeaf() const {
   return BrowserAccessibility::PlatformIsLeaf();
 }
 
+bool BrowserAccessibilityAndroid::CanScrollForward() const {
+  if (!IsSlider())
+    return false;
+
+  float value = GetFloatAttribute(ui::AX_ATTR_VALUE_FOR_RANGE);
+  float max = GetFloatAttribute(ui::AX_ATTR_MAX_VALUE_FOR_RANGE);
+  return value < max;
+}
+
+bool BrowserAccessibilityAndroid::CanScrollBackward() const {
+  if (!IsSlider())
+    return false;
+
+  float value = GetFloatAttribute(ui::AX_ATTR_VALUE_FOR_RANGE);
+  float min = GetFloatAttribute(ui::AX_ATTR_MIN_VALUE_FOR_RANGE);
+  return value > min;
+}
+
 bool BrowserAccessibilityAndroid::IsCheckable() const {
   bool checkable = false;
   bool is_aria_pressed_defined;
@@ -208,6 +226,10 @@ bool BrowserAccessibilityAndroid::IsSelected() const {
   return HasState(ui::AX_STATE_SELECTED);
 }
 
+bool BrowserAccessibilityAndroid::IsSlider() const {
+  return GetRole() == ui::AX_ROLE_SLIDER;
+}
+
 bool BrowserAccessibilityAndroid::IsVisibleToUser() const {
   return !HasState(ui::AX_STATE_INVISIBLE);
 }
@@ -383,11 +405,13 @@ int BrowserAccessibilityAndroid::GetItemIndex() const {
       break;
     case ui::AX_ROLE_SLIDER:
     case ui::AX_ROLE_PROGRESS_INDICATOR: {
-      float value_for_range;
-      if (GetFloatAttribute(
-              ui::AX_ATTR_VALUE_FOR_RANGE, &value_for_range)) {
-        index = static_cast<int>(value_for_range);
-      }
+      // Return a percentage here for live feedback in an AccessibilityEvent.
+      // The exact value is returned in RangeCurrentValue.
+      float min = GetFloatAttribute(ui::AX_ATTR_MIN_VALUE_FOR_RANGE);
+      float max = GetFloatAttribute(ui::AX_ATTR_MAX_VALUE_FOR_RANGE);
+      float value = GetFloatAttribute(ui::AX_ATTR_VALUE_FOR_RANGE);
+      if (max > min && value >= min && value <= max)
+        index = static_cast<int>(((value - min)) * 100 / (max - min));
       break;
     }
   }
@@ -403,14 +427,12 @@ int BrowserAccessibilityAndroid::GetItemCount() const {
       count = PlatformChildCount();
       break;
     case ui::AX_ROLE_SLIDER:
-    case ui::AX_ROLE_PROGRESS_INDICATOR: {
-      float max_value_for_range;
-      if (GetFloatAttribute(ui::AX_ATTR_MAX_VALUE_FOR_RANGE,
-                            &max_value_for_range)) {
-        count = static_cast<int>(max_value_for_range);
-      }
+    case ui::AX_ROLE_PROGRESS_INDICATOR:
+      // An AccessibilityEvent can only return integer information about a
+      // seek control, so we return a percentage. The real range is returned
+      // in RangeMin and RangeMax.
+      count = 100;
       break;
-    }
   }
   return count;
 }
diff --git a/content/browser/accessibility/browser_accessibility_android.h b/content/browser/accessibility/browser_accessibility_android.h
index 8dc2126..70579ab 100644
--- a/content/browser/accessibility/browser_accessibility_android.h
+++ b/content/browser/accessibility/browser_accessibility_android.h
@@ -19,6 +19,8 @@ class CONTENT_EXPORT BrowserAccessibilityAndroid : public BrowserAccessibility {
 
   virtual bool PlatformIsLeaf() const override;
 
+  bool CanScrollForward() const;
+  bool CanScrollBackward() const;
   bool IsCheckable() const;
   bool IsChecked() const;
   bool IsClickable() const;
@@ -38,6 +40,7 @@ class CONTENT_EXPORT BrowserAccessibilityAndroid : public BrowserAccessibility {
   bool IsRangeType() const;
   bool IsScrollable() const;
   bool IsSelected() const;
+  bool IsSlider() const;
   bool IsVisibleToUser() const;
 
   bool CanOpenPopup() const;
diff --git a/content/browser/accessibility/browser_accessibility_manager_android.cc b/content/browser/accessibility/browser_accessibility_manager_android.cc
index 7dbc149..8bc13c8 100644
--- a/content/browser/accessibility/browser_accessibility_manager_android.cc
+++ b/content/browser/accessibility/browser_accessibility_manager_android.cc
@@ -116,6 +116,9 @@ void BrowserAccessibilityManagerAndroid::NotifyAccessibilityEvent(
   if (obj.is_null())
     return;
 
+  BrowserAccessibilityAndroid* android_node =
+      static_cast<BrowserAccessibilityAndroid*>(node);
+
   if (event_type == ui::AX_EVENT_HIDE)
     return;
 
@@ -157,8 +160,6 @@ void BrowserAccessibilityManagerAndroid::NotifyAccessibilityEvent(
     case ui::AX_EVENT_SHOW: {
       // This event is fired when an object appears in a live region.
       // Speak its text.
-      BrowserAccessibilityAndroid* android_node =
-          static_cast<BrowserAccessibilityAndroid*>(node);
       Java_BrowserAccessibilityManager_announceLiveRegionText(
           env, obj.obj(),
           base::android::ConvertUTF16ToJavaString(
@@ -175,6 +176,9 @@ void BrowserAccessibilityManagerAndroid::NotifyAccessibilityEvent(
       if (node->IsEditableText()) {
         Java_BrowserAccessibilityManager_handleEditableTextChanged(
             env, obj.obj(), node->GetId());
+      } else if (android_node->IsSlider()) {
+        Java_BrowserAccessibilityManager_handleSliderChanged(
+            env, obj.obj(), node->GetId());
       }
       break;
     default:
@@ -247,6 +251,8 @@ jboolean BrowserAccessibilityManagerAndroid::PopulateAccessibilityNodeInfo(
   Java_BrowserAccessibilityManager_setAccessibilityNodeInfoBooleanAttributes(
       env, obj, info,
       id,
+      node->CanScrollForward(),
+      node->CanScrollBackward(),
       node->IsCheckable(),
       node->IsChecked(),
       node->IsClickable(),
@@ -465,6 +471,38 @@ void BrowserAccessibilityManagerAndroid::SetSelection(
     SetTextSelection(*node, start, end);
 }
 
+jboolean BrowserAccessibilityManagerAndroid::AdjustSlider(
+    JNIEnv* env, jobject obj, jint id, jboolean increment) {
+  BrowserAccessibility* node = GetFromID(id);
+  if (!node)
+    return false;
+
+  BrowserAccessibilityAndroid* android_node =
+      static_cast<BrowserAccessibilityAndroid*>(node);
+
+  if (!android_node->IsSlider() || !android_node->IsEnabled())
+    return false;
+
+  float value = node->GetFloatAttribute(ui::AX_ATTR_VALUE_FOR_RANGE);
+  float min = node->GetFloatAttribute(ui::AX_ATTR_MIN_VALUE_FOR_RANGE);
+  float max = node->GetFloatAttribute(ui::AX_ATTR_MAX_VALUE_FOR_RANGE);
+  if (max <= min)
+    return false;
+
+  // To behave similarly to an Android SeekBar, move by an increment of
+  // approximately 20%.
+  float original_value = value;
+  float delta = (max - min) / 5.0f;
+  value += (increment ? delta : -delta);
+  value = std::max(std::min(value, max), min);
+  if (value != original_value) {
+    BrowserAccessibilityManager::SetValue(
+        *node, base::UTF8ToUTF16(base::DoubleToString(value)));
+    return true;
+  }
+  return false;
+}
+
 void BrowserAccessibilityManagerAndroid::HandleHoverEvent(
     BrowserAccessibility* node) {
   JNIEnv* env = AttachCurrentThread();
diff --git a/content/browser/accessibility/browser_accessibility_manager_android.h b/content/browser/accessibility/browser_accessibility_manager_android.h
index 63d3268..eb860d4 100644
--- a/content/browser/accessibility/browser_accessibility_manager_android.h
+++ b/content/browser/accessibility/browser_accessibility_manager_android.h
@@ -79,6 +79,7 @@ class CONTENT_EXPORT BrowserAccessibilityManagerAndroid
   void ScrollToMakeNodeVisible(JNIEnv* env, jobject obj, jint id);
   void SetTextFieldValue(JNIEnv* env, jobject obj, jint id, jstring value);
   void SetSelection(JNIEnv* env, jobject obj, jint id, jint start, jint end);
+  jboolean AdjustSlider(JNIEnv* env, jobject obj, jint id, jboolean increment);
 
   // Return the id of the next node in tree order in the direction given by
   // |forwards|, starting with |start_id|, that matches |element_type|,
diff --git a/content/public/android/java/src/org/chromium/content/browser/accessibility/BrowserAccessibilityManager.java b/content/public/android/java/src/org/chromium/content/browser/accessibility/BrowserAccessibilityManager.java
index 0888376..593c2e5 100644
--- a/content/public/android/java/src/org/chromium/content/browser/accessibility/BrowserAccessibilityManager.java
+++ b/content/public/android/java/src/org/chromium/content/browser/accessibility/BrowserAccessibilityManager.java
@@ -291,6 +291,10 @@ public class BrowserAccessibilityManager {
                 }
                 return previousAtGranularity(granularity, extend);
             }
+            case AccessibilityNodeInfo.ACTION_SCROLL_FORWARD:
+                return nativeAdjustSlider(mNativeObj, virtualViewId, true);
+            case AccessibilityNodeInfo.ACTION_SCROLL_BACKWARD:
+                return nativeAdjustSlider(mNativeObj, virtualViewId, false);
             default:
                 break;
         }
@@ -593,6 +597,11 @@ public class BrowserAccessibilityManager {
     }
 
     @CalledByNative
+    private void handleSliderChanged(int id) {
+        sendAccessibilityEvent(id, AccessibilityEvent.TYPE_VIEW_SCROLLED);
+    }
+
+    @CalledByNative
     private void handleContentChanged(int id) {
         int rootId = nativeGetRootId(mNativeObj);
         if (rootId != mCurrentRootId) {
@@ -649,9 +658,10 @@ public class BrowserAccessibilityManager {
 
     @CalledByNative
     private void setAccessibilityNodeInfoBooleanAttributes(AccessibilityNodeInfo node,
-            int virtualViewId, boolean checkable, boolean checked, boolean clickable,
-            boolean editableText, boolean enabled, boolean focusable, boolean focused,
-            boolean password, boolean scrollable, boolean selected, boolean visibleToUser) {
+            int virtualViewId, boolean canScrollForward, boolean canScrollBackward,
+            boolean checkable, boolean checked, boolean clickable, boolean editableText,
+            boolean enabled, boolean focusable, boolean focused, boolean password,
+            boolean scrollable, boolean selected, boolean visibleToUser) {
         node.setCheckable(checkable);
         node.setChecked(checked);
         node.setClickable(clickable);
@@ -677,6 +687,14 @@ public class BrowserAccessibilityManager {
             node.addAction(AccessibilityNodeInfo.ACTION_SET_SELECTION);
         }
 
+        if (canScrollForward) {
+            node.addAction(AccessibilityNodeInfo.ACTION_SCROLL_FORWARD);
+        }
+
+        if (canScrollBackward) {
+            node.addAction(AccessibilityNodeInfo.ACTION_SCROLL_BACKWARD);
+        }
+
         if (focusable) {
             if (focused) {
                 node.addAction(AccessibilityNodeInfo.ACTION_CLEAR_FOCUS);
@@ -942,4 +960,6 @@ public class BrowserAccessibilityManager {
     private native boolean nativePreviousAtGranularity(
             long nativeBrowserAccessibilityManagerAndroid,
             int selectionGranularity, boolean extendSelection, int id, int cursorIndex);
+    private native boolean nativeAdjustSlider(
+            long nativeBrowserAccessibilityManagerAndroid, int id, boolean increment);
 }
diff --git a/content/renderer/accessibility/renderer_accessibility.cc b/content/renderer/accessibility/renderer_accessibility.cc
index 44bc64d..17bc571 100644
--- a/content/renderer/accessibility/renderer_accessibility.cc
+++ b/content/renderer/accessibility/renderer_accessibility.cc
@@ -464,6 +464,7 @@ void RendererAccessibility::OnSetValue(
   }
 
   obj.setValue(value);
+  HandleAXEvent(obj, ui::AX_EVENT_VALUE_CHANGED);
 }
 
 }  // namespace content
diff --git a/content/test/data/accessibility/aria-valuemax-expected-android.txt b/content/test/data/accessibility/aria-valuemax-expected-android.txt
index 0c5f2444..20bfb69 100644
--- a/content/test/data/accessibility/aria-valuemax-expected-android.txt
+++ b/content/test/data/accessibility/aria-valuemax-expected-android.txt
@@ -1,5 +1,5 @@
 android.webkit.WebView focusable focused scrollable
-    android.widget.ProgressBar range item_index=51 item_count=101 range_min=1 range_max=101 range_current_value=51
+    android.widget.ProgressBar range item_index=50 item_count=100 range_min=1 range_max=101 range_current_value=51
     android.view.View range range_min=2 range_max=102 range_current_value=52
-    android.widget.SeekBar range item_index=53 item_count=103 range_min=3 range_max=103 range_current_value=53
-    android.widget.EditText range_min=4 range_max=104 range_current_value=54
+    android.widget.SeekBar range item_index=50 item_count=100 range_min=3 range_max=103 range_current_value=53
+    android.widget.EditText range_min=4 range_max=104 range_current_value=54
\ No newline at end of file
diff --git a/content/test/data/accessibility/aria-valuemin-expected-android.txt b/content/test/data/accessibility/aria-valuemin-expected-android.txt
index 0c5f2444..20bfb69 100644
--- a/content/test/data/accessibility/aria-valuemin-expected-android.txt
+++ b/content/test/data/accessibility/aria-valuemin-expected-android.txt
@@ -1,5 +1,5 @@
 android.webkit.WebView focusable focused scrollable
-    android.widget.ProgressBar range item_index=51 item_count=101 range_min=1 range_max=101 range_current_value=51
+    android.widget.ProgressBar range item_index=50 item_count=100 range_min=1 range_max=101 range_current_value=51
     android.view.View range range_min=2 range_max=102 range_current_value=52
-    android.widget.SeekBar range item_index=53 item_count=103 range_min=3 range_max=103 range_current_value=53
-    android.widget.EditText range_min=4 range_max=104 range_current_value=54
+    android.widget.SeekBar range item_index=50 item_count=100 range_min=3 range_max=103 range_current_value=53
+    android.widget.EditText range_min=4 range_max=104 range_current_value=54
\ No newline at end of file
diff --git a/content/test/data/accessibility/aria-valuenow-expected-android.txt b/content/test/data/accessibility/aria-valuenow-expected-android.txt
index 9d59be2..9bc7f1d 100644
--- a/content/test/data/accessibility/aria-valuenow-expected-android.txt
+++ b/content/test/data/accessibility/aria-valuenow-expected-android.txt
@@ -1,2 +1,2 @@
 android.webkit.WebView focusable focused scrollable
-    android.widget.ProgressBar range item_index=3 range_current_value=3
+    android.widget.ProgressBar range item_count=100 range_current_value=3
\ No newline at end of file
diff --git a/content/test/data/accessibility/input-range-expected-android.txt b/content/test/data/accessibility/input-range-expected-android.txt
index 8e8d7f4..db1b0c6 100644
--- a/content/test/data/accessibility/input-range-expected-android.txt
+++ b/content/test/data/accessibility/input-range-expected-android.txt
@@ -1,3 +1,3 @@
 android.webkit.WebView focusable focused scrollable
     android.view.View
-        android.widget.SeekBar focusable range item_index=5 item_count=10 range_min=1 range_max=10 range_current_value=5
+        android.widget.SeekBar focusable range item_index=44 item_count=100 range_min=1 range_max=10 range_current_value=5
\ No newline at end of file