Add UMA stats for pen palette

ash/common/system/chromeos/palette/palette_ids.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_ids.h"
 #include "base/logging.h"
 
 namespace ash {
 
 std::string PaletteToolIdToString(PaletteToolId tool_id) {
@@ skipping 21 matching lines @@
     case PaletteGroup::ACTION:
       return "ACTION";
     case PaletteGroup::MODE:
       return "MODE";
   }
 
   NOTREACHED();
   return std::string();
 }
 
+PaletteTrayOptions PaletteToolIdToPaletteTrayOptions(PaletteToolId tool_id) {
+  PaletteTrayOptions option = PALETTE_OPTIONS_COUNT;

[jdufault, 2016/09/02 21:54:30]

Can we just return the value directly?

switch (tool_id) {
  case PaletteToolId::CREATE_NOTE:
    return PALETTE_NEW_NOTE;
  // ...
}

[xiaoyinh(OOO Sep 11-29), 2016/09/06 17:40:05]

Done.

+  switch (tool_id) {
+    case PaletteToolId::NONE:
+      break;
+    case PaletteToolId::CREATE_NOTE:
+      option = PALETTE_NEW_NOTE;
+      break;
+    case PaletteToolId::CAPTURE_REGION:
+      option = PALETTE_CAPTURE_REGION;
+      break;
+    case PaletteToolId::CAPTURE_SCREEN:
+      option = PALETTE_CAPTURE_SCREEN;
+      break;
+    case PaletteToolId::LASER_POINTER:
+      option = PALETTE_LASER_POINTER;
+      break;
+    case PaletteToolId::MAGNIFY:
+      option = PALETTE_MAGNIFY;
+      break;
+  }
+
+  return option;
+}
+
 }  // namespace ash