Add UMA stats for pen palette

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

Index: ash/common/system/chromeos/palette/palette_tool.h
diff --git a/ash/common/system/chromeos/palette/palette_tool.h b/ash/common/system/chromeos/palette/palette_tool.h
index bc7c2c2d703c44b73f12fec732af5db634f087ed..cfecf51753ac055ad4a24f9fb0aeba191c62e39b 100644
--- a/ash/common/system/chromeos/palette/palette_tool.h
+++ b/ash/common/system/chromeos/palette/palette_tool.h
@@ -10,6 +10,7 @@
 #include <vector>
 
 #include "ash/ash_export.h"
+#include "ash/common/system/chromeos/palette/palette_ids.h"
 #include "base/callback.h"
 #include "base/macros.h"
 #include "ui/gfx/vector_icon_types.h"
@@ -52,6 +53,12 @@ class ASH_EXPORT PaletteTool {
     // Returns the root window.
     virtual WmWindow* GetWindow() = 0;
 
+    // Record usage of each pen palette option.
+    virtual void RecordPaletteOptionsUsage(PaletteTrayOptions option) = 0;
+
+    // Record mode cancellation of pen palette.
+    virtual void RecordPaletteModeCancellation(PaletteModeCancelType type) = 0;
+
    private:
     DISALLOW_COPY_AND_ASSIGN(Delegate);
   };