Add UMA stats for pen palette

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

Index: ash/common/system/chromeos/palette/palette_tool_manager.h
diff --git a/ash/common/system/chromeos/palette/palette_tool_manager.h b/ash/common/system/chromeos/palette/palette_tool_manager.h
index c2375bd61bf96f5c3e272fa97c4efc490c86c792..198757c8c8a70560aa0f2efd9ef6142078c5d5b3 100644
--- a/ash/common/system/chromeos/palette/palette_tool_manager.h
+++ b/ash/common/system/chromeos/palette/palette_tool_manager.h
@@ -48,6 +48,12 @@ class ASH_EXPORT PaletteToolManager : public PaletteTool::Delegate {
     // Return the window associated with this palette.
     virtual WmWindow* GetWindow() = 0;
 
+    // Record usage of each pen palette option.
+    virtual void RecordPaletteOptionsUsage(ash::PaletteTrayOptions option) = 0;
+
+    // Record mode cancellation of pen palette.
+    virtual void RecordPaletteModeCancellation(PaletteModeCancelType type) = 0;
+
    private:
     DISALLOW_COPY_AND_ASSIGN(Delegate);
   };
@@ -90,6 +96,8 @@ class ASH_EXPORT PaletteToolManager : public PaletteTool::Delegate {
   void DisableTool(PaletteToolId tool_id) override;
   void HidePalette() override;
   WmWindow* GetWindow() override;
+  void RecordPaletteOptionsUsage(ash::PaletteTrayOptions option) override;
+  void RecordPaletteModeCancellation(PaletteModeCancelType type) override;
 
   PaletteTool* FindToolById(PaletteToolId tool_id) const;