[Athena] Add status icons and system time to the desktop background

athena/system/time_view.cc

+// Copyright 2014 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 "athena/system/time_view.h"
+
+#include "base/i18n/time_formatting.h"
+#include "third_party/skia/include/core/SkColor.h"
+#include "ui/views/border.h"
+
+namespace athena {
+namespace {
+
+// Amount of slop to add into the timer to make sure we're into the next minute
+// when the timer goes off.
+const int kTimerSlopSeconds = 1;
+
+}  // namespace
+
+TimeView::TimeView() {
+  SetHorizontalAlignment(gfx::ALIGN_LEFT);
+  SetEnabledColor(SK_ColorWHITE);
+  SetAutoColorReadabilityEnabled(false);
+  SetFontList(gfx::FontList().DeriveWithStyle(gfx::Font::BOLD));
+
+  const int kHorizontalSpacing = 10;
+  const int kVerticalSpacing = 3;
+  SetBorder(views::Border::CreateEmptyBorder(kVerticalSpacing,
+                                             kHorizontalSpacing,
+                                             kVerticalSpacing,
+                                             kHorizontalSpacing));
+
+  UpdateText();
+}
+
+TimeView::~TimeView() {
+}
+
+void TimeView::SetTimer(base::Time now) {
+  // Try to set the timer to go off at the next change of the minute. We don't
+  // want to have the timer go off more than necessary since that will cause
+  // the CPU to wake up and consume power.
+  base::Time::Exploded exploded;
+  now.LocalExplode(&exploded);
+
+  // Often this will be called at minute boundaries, and we'll actually want
+  // 60 seconds from now.
+  int seconds_left = 60 - exploded.second;
+  if (seconds_left == 0)
+    seconds_left = 60;
+
+  // Make sure that the timer fires on the next minute. Without this, if it is
+  // called just a teeny bit early, then it will skip the next minute.
+  seconds_left += kTimerSlopSeconds;
+
+  timer_.Stop();
+  timer_.Start(
+      FROM_HERE, base::TimeDelta::FromSeconds(seconds_left),
+      this, &TimeView::UpdateText);
+}
+
+void TimeView::UpdateText() {
+  base::Time now = base::Time::Now();
+  SetText(base::TimeFormatTimeOfDayWithHourClockType(
+      now, base::k12HourClock, base::kKeepAmPm));
+  SetTimer(now);
+}
+
+}  // namespace athena