Add UMA stats for pen palette

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/common/system/chromeos/palette/palette_tool_manager.h"
 
 #include <algorithm>
 
 #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 {
 
 PaletteToolManager::PaletteToolManager(Delegate* delegate)
     : delegate_(delegate) {
   DCHECK(delegate_);
 }
 
 PaletteToolManager::~PaletteToolManager() {}
 
 void PaletteToolManager::AddTool(std::unique_ptr<PaletteTool> tool) {
   // The same PaletteToolId cannot be registered twice.
   DCHECK_EQ(0, std::count_if(tools_.begin(), tools_.end(),
                              [&tool](const std::unique_ptr<PaletteTool>& t) {
                                return t->GetToolId() == tool->GetToolId();
                              }));
 
   tools_.emplace_back(std::move(tool));
 }
 
 void PaletteToolManager::ActivateTool(PaletteToolId tool_id) {
   PaletteTool* new_tool = FindToolById(tool_id);
   DCHECK(new_tool);
 
   PaletteTool* previous_tool = active_tools_[new_tool->GetGroup()];
 
   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();
 
   delegate_->OnActiveToolChanged();
 }
 
 void PaletteToolManager::DeactivateTool(PaletteToolId tool_id) {
   PaletteTool* tool = FindToolById(tool_id);
   DCHECK(tool);
@@ skipping 58 matching lines @@
 }
 
 void PaletteToolManager::HidePalette() {
   delegate_->HidePalette();
 }
 
 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)
       return tool.get();
   }
 
   return nullptr;
 }
 
 }  // namespace ash