Add UMA stats for pen palette

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

Index: ash/common/system/chromeos/palette/palette_tool_manager.cc
diff --git a/ash/common/system/chromeos/palette/palette_tool_manager.cc b/ash/common/system/chromeos/palette/palette_tool_manager.cc
index b9a306ec2d91e4103125ffffa00a45812d153ecf..d9a79b806079e45e7820862a2219a1e5768f5ab0 100644
--- a/ash/common/system/chromeos/palette/palette_tool_manager.cc
+++ b/ash/common/system/chromeos/palette/palette_tool_manager.cc
@@ -9,6 +9,7 @@
 #include "ash/common/system/chromeos/palette/palette_tool.h"
 #include "ash/resources/vector_icons/vector_icons.h"
 #include "base/bind.h"
+#include "base/metrics/histogram_macros.h"
 
 namespace ash {
 
@@ -38,8 +39,11 @@ void PaletteToolManager::ActivateTool(PaletteToolId tool_id) {
   if (new_tool == previous_tool)
     return;
 
-  if (previous_tool)
+  if (previous_tool) {
     previous_tool->OnDisable();
+    RecordPaletteModeCancellation(PaletteToolIdToPaletteModeCancelType(
+        previous_tool->GetToolId(), true /*is_switched*/));
+  }
 
   active_tools_[new_tool->GetGroup()] = new_tool;
   new_tool->OnEnable();
@@ -118,6 +122,15 @@ WmWindow* PaletteToolManager::GetWindow() {
   return delegate_->GetWindow();
 }
 
+void PaletteToolManager::RecordPaletteOptionsUsage(PaletteTrayOptions option) {
+  return delegate_->RecordPaletteOptionsUsage(option);
+}
+
+void PaletteToolManager::RecordPaletteModeCancellation(
+    PaletteModeCancelType type) {
+  return delegate_->RecordPaletteModeCancellation(type);
+}
+
 PaletteTool* PaletteToolManager::FindToolById(PaletteToolId tool_id) const {
   for (const std::unique_ptr<PaletteTool>& tool : tools_) {
     if (tool->GetToolId() == tool_id)