Add a battery icon to the right of Tether networks in system tray.

ash/system/network/network_list.cc

Index: ash/system/network/network_list.cc
diff --git a/ash/system/network/network_list.cc b/ash/system/network/network_list.cc
index 5415eabb3c6d5b5315992a82b241e91250cb3815..5a5e53eab5cff541f056e5724a938d93333c93dc 100644
--- a/ash/system/network/network_list.cc
+++ b/ash/system/network/network_list.cc
@@ -6,6 +6,7 @@
 
 #include <memory>
 
+#include "ash/resources/vector_icons/vector_icons.h"
 #include "ash/shell.h"
 #include "ash/shell_port.h"
 #include "ash/strings/grit/ash_strings.h"
@@ -22,6 +23,7 @@
 #include "ash/system/tray/tray_popup_item_style.h"
 #include "ash/system/tray/tray_popup_utils.h"
 #include "ash/system/tray/tri_view.h"
+#include "base/i18n/number_formatting.h"
 #include "base/memory/ptr_util.h"
 #include "base/strings/string16.h"
 #include "base/strings/utf_string_conversions.h"
@@ -35,6 +37,7 @@
 #include "third_party/cros_system_api/dbus/service_constants.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/base/l10n/l10n_util.h"
+#include "ui/gfx/canvas.h"
 #include "ui/gfx/font.h"
 #include "ui/gfx/image/image_skia.h"
 #include "ui/gfx/paint_vector_icon.h"
@@ -577,9 +580,55 @@ void NetworkListView::UpdateViewForNetwork(HoverHighlightView* view,
   else if (info.connecting)
     SetupConnectingScrollListItem(view);
   view->SetTooltipText(info.tooltip);
-  views::View* controlled_icon = CreateControlledByExtensionView(info);
-  if (controlled_icon)
-    view->AddRightView(controlled_icon);
+
+  // Add an additional icon to the right of the label for networks
+  // that require it (e.g. Tether, controlled by extension).
+  views::View* power_icon = CreatePowerStatusView(info);
+  if (power_icon) {
+    view->AddRightView(power_icon);
+  } else {
+    views::View* controlled_icon = CreateControlledByExtensionView(info);
+    if (controlled_icon)
+      view->AddRightView(controlled_icon);
+  }
+}
+
+views::View* NetworkListView::CreatePowerStatusView(const NetworkInfo& info) {
+  // Mobile can be Cellular or Tether.
+  if (info.type != NetworkInfo::Type::MOBILE)
+    return nullptr;
+
+  const chromeos::NetworkState* network =
+      NetworkHandler::Get()->network_state_handler()->GetNetworkStateFromGuid(
+          info.guid);
+
+  // Only return a battery icon for Tether network type.
+  if (!NetworkTypePattern::Tether().MatchesType(network->type()))
+    return nullptr;
+
+  views::ImageView* icon = TrayPopupUtils::CreateMoreImageView();
+  gfx::Size canvas_size = gfx::Size(kMenuIconSize, kMenuIconSize);

[Evan Stade, 2017/06/14 18:04:38]

Hi all,

I am making some changes to the battery icon so I noticed this CL. There are a
couple things I see to keep in mind for the future. The first is that this is
using an icon at a size that it's not designed for. It's subtle but you can tell
the icon should only be displayed at 16dip because that's what the 1x.icon file
specifies. (I'm working on adding a DCHECK for this but can't do so until errant
callsites are cleaned up.) Displaying at any other size won't have guaranteed
sharp lines: in this case, if you zoom in you can see that it's a bit blurrier
than we'd like. The second observation is that this copies a lot of code from
PowerStatus, which should instead be shared. The final observation is that
assuming a 1x scale and using CreateFrom1xBitmap is not appropriate as the icon
for non-1x scales is slightly different.

I will fold these suggestions into my change but I wanted to share them here for
future reference. Thanks and sorry for the late notice.

[Kyle Horimoto, 2017/06/15 20:14:23]

Thanks for the heads-up, Evan! Just wanted to clarify - you'll be fixing this
issue in a follow-up CL (so we don't have to submit a change ourselves), right?

Please CC us on your change so we can see the correct way to use these icons -
thank you! :)

+  gfx::Canvas canvas(canvas_size, 1.0f, false /* opaque */);
+
+  // Paint the battery's base (background) color.
+  PaintVectorIcon(&canvas, kSystemTrayBatteryIcon, kMenuIconSize,
+                  kMenuIconColorDisabled);
+  // Paint the charged portion of the battery.
+  const int charge_height = network->battery_percentage() * kMenuIconSize / 100;
+  gfx::Rect clip_rect(0, kMenuIconSize - charge_height, kMenuIconSize,
+                      charge_height);
+  canvas.Save();
+  canvas.ClipRect(clip_rect);
+  PaintVectorIcon(&canvas, kSystemTrayBatteryIcon, kMenuIconSize,
+                  kMenuIconColor);
+  canvas.Restore();
+
+  // Show the battery icon with correct charge height.
+  icon->SetImage(gfx::ImageSkia::CreateFrom1xBitmap(canvas.GetBitmap()));
+  // Show the numeric battery percentage on hover.
+  icon->SetTooltipText(base::FormatPercent(network->battery_percentage()));
+
+  return icon;
 }
 
 views::View* NetworkListView::CreateControlledByExtensionView(