Fuchsia port of base/time, with some refactoring of POSIX time modules.

base/BUILD.gn

Index: base/BUILD.gn
diff --git a/base/BUILD.gn b/base/BUILD.gn
index 49e16f5c0bdedc4956a7bf827fdf614834b8674c..d022a6cb4d1b7fd0ac5be73d0b9dd79bd8a4bdc9 100644
--- a/base/BUILD.gn
+++ b/base/BUILD.gn
@@ -924,9 +924,6 @@ component("base") {
     "time/tick_clock.h",
     "time/time.cc",
     "time/time.h",
-    "time/time_mac.cc",

[Lei Zhang, 2017/05/17 08:34:16]

This has the advantage of the files are mostly listed together and almost never
repeated. Do we want to keep it like this, let the default
sources_assignment_filter rules in build/config/BUILDCONFIG.gn do their thing,
and tweak the sources afterwards?

i.e.
1) List everything here.
2) Exclude time_exploded_posix.cc and time_now_posix.cc just below line 1468.
3) Add a new conditional rule to exclude time_now_posix.cc for Fuchsia.

[miu, 2017/05/18 02:52:38]

I was discussing this with thakis@ at on the code review that added the Fuchsia
build config. The advice I got there was that we want to remove the use of
sources_assignment_filter in the long-term, and instead explicitly "source +=
[...]" files for each platform. To be fair, I'm not sure if there was an
official decision on this, but scottmg@ agreed and also mentioned Brett had made
similar comments.

If you're curious, here's the discussion on that:
https://codereview.chromium.org/2784063002/#msg54

Also, FWIW, the top of this particular BUILD.gn file has a related comment, that
states we should prefer to mention files in more than one list so that it's more
clear under which conditions it will be built.

Sound good to you, to leave it as I have it now?

[Lei Zhang, 2017/05/18 19:06:12]

I've always found the sources_assignment_filter to be convinent. Oftentimes, but
not always, it does the right thing. But sure, let's leave this as is, given the
comments at the top of the file.

-    "time/time_posix.cc",
-    "time/time_win.cc",
     "timer/elapsed_timer.cc",
     "timer/elapsed_timer.h",
     "timer/hi_res_timer_manager.h",
@@ -1345,6 +1342,7 @@ component("base") {
       "power_monitor/power_monitor_device_source_win.cc",
       "profiler/win32_stack_frame_unwinder.cc",
       "profiler/win32_stack_frame_unwinder.h",
+      "time/time_win.cc",
     ]
 
     sources -= [
@@ -1452,6 +1450,8 @@ component("base") {
     sources += [
       "mac/scoped_typeref.h",
       "power_monitor/power_monitor_device_source_mac.mm",
+      "time/time_conversion_posix.cc",
+      "time/time_mac.cc",
     ]
 
     libs = [
@@ -1597,12 +1597,30 @@ component("base") {
       "process/memory_stubs.cc",
       "strings/sys_string_conversions_mac.mm",
       "threading/platform_thread_mac.mm",
+      "time/time_conversion_posix.cc",
       "time/time_mac.cc",
     ]
 
     set_sources_assignment_filter(sources_assignment_filter)
   }
 
+  # Fuchsia.
+  if (is_fuchsia) {
+    sources += [
+      "time/time_conversion_posix.cc",
+      "time/time_exploded_posix.cc",
+      "time/time_fuchsia.cc",
+    ]
+  }
+
+  if (is_posix && !is_fuchsia && !is_mac && !is_ios) {
+    sources += [
+      "time/time_conversion_posix.cc",
+      "time/time_exploded_posix.cc",
+      "time/time_now_posix.cc",
+    ]
+  }
+
   if (is_posix && !is_mac && !is_ios && !is_android && !is_chromeos) {
     sources += [ "power_monitor/power_monitor_device_source_posix.cc" ]
   }