Add UMA stats for pen palette

ash/common/system/chromeos/palette/common_palette_tool.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/common_palette_tool.h"
 
 #include "ash/common/shelf/shelf_constants.h"
 #include "ash/common/system/chromeos/palette/palette_ids.h"
 #include "ash/common/system/chromeos/palette/palette_tool_manager.h"
 #include "ash/common/system/tray/hover_highlight_view.h"
 #include "ash/common/system/tray/view_click_listener.h"
 #include "base/logging.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/strings/utf_string_conversions.h"
 #include "grit/ash_resources.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/color_palette.h"
 #include "ui/gfx/paint_vector_icon.h"
 #include "ui/views/border.h"
 
 namespace ash {
 namespace {
 
@@ skipping 21 matching lines @@
   return CreateDefaultView(
       base::ASCIIToUTF16("[TODO] " + PaletteToolIdToString(GetToolId())));
 }
 
 void CommonPaletteTool::OnViewDestroyed() {
   highlight_view_ = nullptr;
 }
 
 void CommonPaletteTool::OnEnable() {
   PaletteTool::OnEnable();
+  start_time_ = base::TimeTicks::Now();
 
   if (highlight_view_) {
     highlight_view_->SetHighlight(true);
     highlight_view_->SetRightIconVisible(true);
   }
 }
 
 void CommonPaletteTool::OnDisable() {
   PaletteTool::OnDisable();
 
+  if (GetToolId() == ash::PaletteToolId::LASER_POINTER) {

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

What about something like

if (ShouldRecordUma(GetToolId())
  UMA_HISTOGRAM...(GetUmaName(GetToolId()), ...);

And then ShouldRecordUma / GetUmaName are defined in the anonymous namespace of
this file.

Though to avoid pulling in every tool type for this specific file maybe we want
to do something like

if (GetActiveDurationUmaName())
  UMA_HISTOGRAM(GetActiveDurationUmaName(), ...)

Where GetActiveDurationUmaName() is a virtual method that returns an std::string
instance. If the tool wants to record an UMA value, it returns a non-empty
string.

[Ilya Sherman, 2016/09/02 22:02:49]

Histogram names passed to UMA_HISTOGRAM_ macros must be runtime constant, so I
don't think your suggestion will work.  You'll either need to call the
underlying C++ code directly, or have different code paths for different
histogram names.

+    UMA_HISTOGRAM_LONG_TIMES_100("Ash.Shelf.Palette.InLaserPointerMode",

[Ilya Sherman, 2016/09/02 21:39:30]

Hmm, are values under 100 ms at all likely?  I would recommend using an
UMA_HISTOGRAM_CUSTOM_TIMES, with 50 buckets, and a higher minimum.  Ditto below.

[xiaoyinh(OOO Sep 11-29), 2016/09/06 17:40:04]

Done.

+                                 base::TimeTicks::Now() - start_time_);
+  } else if (GetToolId() == ash::PaletteToolId::MAGNIFY) {
+    UMA_HISTOGRAM_LONG_TIMES_100("Ash.Shelf.Palette.InMagnifyMode",
+                                 base::TimeTicks::Now() - start_time_);
+  }
+
   if (highlight_view_) {
     highlight_view_->SetHighlight(false);
     highlight_view_->SetRightIconVisible(false);
   }
 }
 
 void CommonPaletteTool::OnViewClicked(views::View* sender) {
+  delegate()->RecordPaletteMetrics(
+      PaletteToolIdToPaletteTrayOptions(GetToolId()));
   if (enabled())
     delegate()->DisableTool(GetToolId());
   else
     delegate()->EnableTool(GetToolId());
 }
 
 views::View* CommonPaletteTool::CreateDefaultView(const base::string16& name) {
   gfx::ImageSkia icon =
       CreateVectorIcon(GetPaletteIconId(), kIconSize, gfx::kChromeIconGrey);
   gfx::ImageSkia check = CreateVectorIcon(gfx::VectorIconId::CHECK_CIRCLE,
                                           kIconSize, gfx::kGoogleGreen700);
 
   highlight_view_ = new HoverHighlightView(this);
   highlight_view_->SetBorder(
       views::Border::CreateEmptyBorder(0, kExtraMarginFromLeftEdge, 0, 0));
   highlight_view_->AddIconAndLabelCustomSize(icon, name, false, kIconSize,
                                              kMarginFromEdges,
                                              kMarginBetweenIconAndText);
   highlight_view_->AddRightIcon(check, kIconSize);
 
   if (enabled())
     highlight_view_->SetHighlight(true);
   else
     highlight_view_->SetRightIconVisible(false);
 
   return highlight_view_;
 }
 
 }  // namespace ash