BatteryStatus: fix chargingTime() to follow the specification.

If the battery status is unknown, the charging time should be
0 instead of Infinity. The reason being that in that case, the
battery status is reflected as a plugged and fully charged battery.

BUG=122593

Review URL: https://codereview.chromium.org/203693003

git-svn-id: svn://svn.chromium.org/blink/trunk@170338 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/LayoutTests/battery-status/test-battery-status-basic-expected.txt

@@ -2,7 +2,7 @@ This test prints the default battery status values.
 
 Charging Status: Charging
 
-Charging Time: Infinity
+Charging Time: 0
 
 Discharging Time: Infinity
 

third_party/WebKit/LayoutTests/fast/dom/Window/property-access-on-cached-properties-after-frame-navigated-expected.txt

@@ -42,7 +42,7 @@ PASS window.cached_navigator.userAgent is ''
 PASS window.cached_navigator.vendor is window.navigator.vendor
 PASS window.cached_navigator.vendorSub is ''
 FAIL window.cached_navigator_battery.charging should be false. Was true.
-FAIL window.cached_navigator_battery.chargingTime should be 0. Was Infinity.
+PASS window.cached_navigator_battery.chargingTime is 0
 FAIL window.cached_navigator_battery.dischargingTime should be 0. Was Infinity.
 FAIL window.cached_navigator_battery.level should be 0. Was 1.
 PASS window.cached_navigator_battery.onchargingchange is null

third_party/WebKit/LayoutTests/fast/dom/Window/property-access-on-cached-properties-after-frame-removed-and-gced-expected.txt

@@ -42,7 +42,7 @@ PASS window.cached_navigator.userAgent is ''
 PASS window.cached_navigator.vendor is window.navigator.vendor
 PASS window.cached_navigator.vendorSub is ''
 FAIL window.cached_navigator_battery.charging should be false. Was true.
-FAIL window.cached_navigator_battery.chargingTime should be 0. Was Infinity.
+PASS window.cached_navigator_battery.chargingTime is 0
 FAIL window.cached_navigator_battery.dischargingTime should be 0. Was Infinity.
 FAIL window.cached_navigator_battery.level should be 0. Was 1.
 PASS window.cached_navigator_battery.onchargingchange is null

third_party/WebKit/LayoutTests/fast/dom/Window/property-access-on-cached-properties-after-frame-removed-expected.txt

@@ -42,7 +42,7 @@ PASS window.cached_navigator.userAgent is ''
 PASS window.cached_navigator.vendor is window.navigator.vendor
 PASS window.cached_navigator.vendorSub is ''
 FAIL window.cached_navigator_battery.charging should be false. Was true.
-FAIL window.cached_navigator_battery.chargingTime should be 0. Was Infinity.
+PASS window.cached_navigator_battery.chargingTime is 0
 FAIL window.cached_navigator_battery.dischargingTime should be 0. Was Infinity.
 FAIL window.cached_navigator_battery.level should be 0. Was 1.
 PASS window.cached_navigator_battery.onchargingchange is null

third_party/WebKit/LayoutTests/fast/dom/Window/property-access-on-cached-window-after-frame-removed-expected.txt

@@ -40,7 +40,7 @@ PASS childWindow.navigator.appCodeName is window.navigator.appCodeName
 PASS childWindow.navigator.appName is window.navigator.appName
 PASS childWindow.navigator.appVersion is ''
 FAIL childWindow.navigator.battery.charging should be false. Was true.
-FAIL childWindow.navigator.battery.chargingTime should be 0. Was Infinity.
+PASS childWindow.navigator.battery.chargingTime is 0
 FAIL childWindow.navigator.battery.dischargingTime should be 0. Was Infinity.
 FAIL childWindow.navigator.battery.level should be 0. Was 1.
 PASS childWindow.navigator.battery.onchargingchange is null

third_party/WebKit/Source/modules/battery/BatteryManager.cpp

@@ -34,9 +34,16 @@ bool BatteryManager::charging()
 
 double BatteryManager::chargingTime()
 {
-    if (!m_batteryStatus || !m_batteryStatus->charging())
+    if (!m_batteryStatus)
+        return 0;
+
+    if (!m_batteryStatus->charging())
         return std::numeric_limits<double>::infinity();
 
+    // The spec requires that if level == 1.0, chargingTime == 0 but this has to
+    // be implement by the backend. Adding this assert will help enforcing it.
+    ASSERT(level() != 1.0 && m_batteryStatus->chargingTime() == 0.0);
+
     return m_batteryStatus->chargingTime();
 }