record screen brightness and a timestamp to estimate the power consumption of screen

Get clock time via timeService when setting screen brightness. PowerStatsService measures the duration of the screen brightness to estimate the power consumption.

Implement a clock_gettime function in timeService to help each component obtains the clock time.

Comment on attachment 780804 [details] [diff] [review] clock_gettime implementation Review of attachment 780804 [details] [diff] [review]: ----------------------------------------------------------------- ::: dom/time/TimeService.cpp @@ +39,5 @@ > + const uint64_t convert = 1000000; > + clock_gettime(CLOCK_MONOTONIC, &t); > + *currTime = (uint64_t)((t.tv_sec)*1000000000LL + t.tv_nsec); > + // convert nano second to micro second > + *currTime = *currTime / convert; Please implement hal::GetClockTime() here rather than use the system call directly. These call should not be run in others platform. ::: dom/time/nsITimeService.idl @@ +15,5 @@ > /* Set the system time. > * > * The |aTimeInMS| argument is the time in milliseconds since the epoch. > */ > void set(in int64_t aTimeInMS); Please add comments here.

Comment on attachment 780803 [details] [diff] [review] Screen power consumption estimation Review of attachment 780803 [details] [diff] [review]: ----------------------------------------------------------------- ::: dom/power/PowerStatsService.jsm @@ +353,5 @@ > + if (index === "screen") { > + let brightness = value[1]; > + let timeStampInt = parseInt(timeStamp, DECIMAL); > + let startTime = systemPowerInfo[index].startTime; > + systemPowerInfo[index].time += (timeStampInt - startTime) * brightness; Can you explain the algorithm here ?

Previous patch saves time in power info. This patch saves power consumption(mA) in power info.

Fix bugs.

Originally, PowerStatsService passively collect the timestamp. Once PowerStatsService receive the timestamp, PowerStatsService starts to calculating the power consumption. The power consumption information is not update to date if PowerStatsService does not receive a timestamp. So, we add updateSystemInfo function to support actively update screen power consumption before return information to Gaia.

Firefox OS is not being worked on