Deprecating high-conflict accelerators

ash/accelerators/accelerator_table.h

Index: ash/accelerators/accelerator_table.h
diff --git a/ash/accelerators/accelerator_table.h b/ash/accelerators/accelerator_table.h
index 1d478a0f8a9b3e8b073c6626d09f7b0385b960d5..0a01641f4815669c0603203b577f139d49cdc7b0 100644
--- a/ash/accelerators/accelerator_table.h
+++ b/ash/accelerators/accelerator_table.h
@@ -153,10 +153,44 @@ struct AcceleratorData {
   AcceleratorAction action;
 };
 
+// Gathers the needed data to handle deprecated accelerators.
+struct DeprecatedAcceleratorData {
+  // The old deprecated accelerator.
+  AcceleratorData deprecated_accelerator;
+
+  // The name of the UMA histogram that will be used to measure the deprecated
+  // v.s. new accelerator usage.
+  const char* uma_histogram_name;
+
+  // The ID of the localized notification message to show to users informing
+  // them about the deprecation.
+  int notification_message_id;
+
+  // Specifies whether the deprecated accelerator is still enabled to do its
+  // associated action.
+  bool deprecated_enabled;
+};
+
+// The ID of the MessageCenter notifications of deprecated accelerators.
+const char kDeprecatedAcceleratorNotificationId[] = "deprecated_accelerator";
+
+// This will be used for the UMA stats to measure the how many users are using
+// the old v.s. new accelerators.
+enum DeprecatedAcceleratorUsage {
+  DEPRECATED_USED = 0,     // The deprecated accelerator is used.
+  NEW_USED,                // The new accelerator is used.
+  DEPRECATED_USAGE_COUNT,  // Maximum value of this enum for histogram use.
+};
+
 // Accelerators handled by AcceleratorController.
 ASH_EXPORT extern const AcceleratorData kAcceleratorData[];
 ASH_EXPORT extern const size_t kAcceleratorDataLength;
 
+// The list of the deprecated accelerators along with their new replacing ones
+// and how to handle them.
+ASH_EXPORT extern const DeprecatedAcceleratorData kDeprecatedAccelerators[];
+ASH_EXPORT extern const size_t kDeprecatedAcceleratorsLength;
+
 // Debug accelerators. Debug accelerators are only enabled when the "Debugging
 // keyboard shortcuts" flag (--ash-debug-shortcuts) is enabled. Debug actions
 // are always run (similar to reserved actions).