Add UMA stats for pen palette

ash/common/system/chromeos/palette/palette_ids.h

Index: ash/common/system/chromeos/palette/palette_ids.h
diff --git a/ash/common/system/chromeos/palette/palette_ids.h b/ash/common/system/chromeos/palette/palette_ids.h
index 31dfe1323b3a674d1e686637f8241cd5fb770250..5b702e8ca07b4af019463a62d29e4deea0acd237 100644
--- a/ash/common/system/chromeos/palette/palette_ids.h
+++ b/ash/common/system/chromeos/palette/palette_ids.h
@@ -27,10 +27,38 @@ enum class PaletteToolId {
   MAGNIFY,
 };
 
+// Usage of each pen palette option. This enum is used to back an UMA histogram
+// and should be treated as append-only.
+enum PaletteTrayOptions {
+  PALETTE_CLOSED_NO_ACTION = 0,
+  PALETTE_SETTINGS_BUTTON,
+  PALETTE_HELP_BUTTON,
+  PALETTE_CAPTURE_REGION,
+  PALETTE_CAPTURE_SCREEN,
+  PALETTE_NEW_NOTE,
+  PALETTE_MAGNIFY,
+  PALETTE_LASER_POINTER,
+  PALETTE_OPTIONS_COUNT
+};
+
+// Type of palette mode cancellation. This enum is used to back an UMA histogram
+// and should be treated as append-only.
+enum PaletteModeCancelType {
+  PALETTE_MODE_LASER_POINTER_CANCELLED = 0,
+  PALETTE_MODE_LASER_POINTER_SWITCHED,
+  PALETTE_MODE_MAGNIFY_CANCELLED,
+  PALETTE_MODE_MAGNIFY_SWITCHED,
+  PALETTE_MODE_CANCEL_TYPE_COUNT
+};
+
 // Helper functions that convert PaletteToolIds and PaletteGroups to strings.
 ASH_EXPORT std::string PaletteToolIdToString(PaletteToolId tool_id);
 ASH_EXPORT std::string PaletteGroupToString(PaletteGroup group);
 
+// Helper functions that convert PaletteToolIds to PaletteTrayOptions.
+ASH_EXPORT PaletteTrayOptions
+PaletteToolIdToPaletteTrayOptions(PaletteToolId tool_id);
+
 }  // namespace ash
 
 #endif  // ASH_COMMON_SYSTEM_CHROMEOS_PALETTE_PALETTE_IDS_H_