Adds extension APIs of events on changing volume.

chrome/browser/extensions/extension_accessibility_api_constants.cc

Index: chrome/browser/extensions/extension_accessibility_api_constants.cc
diff --git a/chrome/browser/extensions/extension_accessibility_api_constants.cc b/chrome/browser/extensions/extension_accessibility_api_constants.cc
index 6cad35e6cff72bf02a76035530ccdcfcd02694f7..dd6d8a5a189172e8d56df3d6016fe5396656af1f 100644
--- a/chrome/browser/extensions/extension_accessibility_api_constants.cc
+++ b/chrome/browser/extensions/extension_accessibility_api_constants.cc
@@ -18,6 +18,8 @@ const char kSelectionStartKey[] = "details.selectionStart";
 const char kSelectionEndKey[] = "details.selectionEnd";
 const char kCheckedKey[] = "details.isChecked";
 const char kHasSubmenuKey[] = "details.hasSubmenu";
+const char kVolumeKey[] = "details.volume";
+const char kIsVolumeMutedKey[] = "details.isVolumeMuted";
 
 // Events.
 const char kOnWindowOpened[] = "experimental.accessibility.onWindowOpened";
@@ -27,6 +29,7 @@ const char kOnControlAction[] = "experimental.accessibility.onControlAction";
 const char kOnTextChanged[] = "experimental.accessibility.onTextChanged";
 const char kOnMenuOpened[] = "experimental.accessibility.onMenuOpened";
 const char kOnMenuClosed[] = "experimental.accessibility.onMenuClosed";
+const char kOnVolumeChanged[] = "experimental.accessibility.onVolumeChanged";
 
 // Types of controls that can receive accessibility events.
 const char kTypeButton[] = "button";
@@ -39,6 +42,7 @@ const char kTypeMenuItem[] = "menuitem";
 const char kTypeRadioButton[] = "radiobutton";
 const char kTypeTab[] = "tab";
 const char kTypeTextBox[] = "textbox";
+const char kTypeVolume[] = "volume";
 const char kTypeWindow[] = "window";
 
 }  // namespace extension_accessibility_api_constants