Add UMA stats for pen palette

ash/common/system/chromeos/palette/palette_tool_manager_unittest.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.h"
 #include "ash/common/system/chromeos/palette/palette_tool_manager.h"
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
@@ skipping 40 matching lines @@
   ~PaletteToolManagerTest() override {}
 
  protected:
   // PaletteToolManager::Delegate:
   void HidePalette() override {}
   void OnActiveToolChanged() override { ++tool_changed_count_; }
   WmWindow* GetWindow() override {
     NOTREACHED();
     return nullptr;
   }
+  void RecordPaletteOptionsUsage(PaletteTrayOptions option) override {}
+  void RecordPaletteModeCancellation(PaletteModeCancelType type) override {}
 
   // PaletteTool::Delegate:
   void EnableTool(PaletteToolId tool_id) override {}
   void DisableTool(PaletteToolId tool_id) override {}
 
   // Helper method for returning an unowned pointer to the constructed tool
   // while also adding it to the PaletteToolManager.
   TestTool* BuildTool(PaletteGroup group, PaletteToolId tool_id) {
     auto* tool = new TestTool(this, group, tool_id);
     palette_tool_manager_->AddTool(base::WrapUnique(tool));
@@ skipping 54 matching lines @@
 
   // Activating an already active tool will not do anything.
   palette_tool_manager_->ActivateTool(action_1->GetToolId());
   EXPECT_TRUE(action_1->enabled());
   EXPECT_FALSE(action_2->enabled());
   palette_tool_manager_->ActivateTool(action_1->GetToolId());
   EXPECT_TRUE(action_1->enabled());
   EXPECT_FALSE(action_2->enabled());
   palette_tool_manager_->DeactivateTool(action_1->GetToolId());
 }