use base::Time constants in mojo instead of defining locally

mojo/apps/js/bindings/monotonic_clock.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 "mojo/apps/js/bindings/monotonic_clock.h"
 
+#include "base/time/time.h"
 #include "gin/object_template_builder.h"
 #include "gin/per_isolate_data.h"
 #include "gin/public/wrapper_info.h"
 #include "mojo/public/cpp/system/core.h"
 
 namespace mojo {
 namespace apps {
 
 namespace {
 
 gin::WrapperInfo g_wrapper_info = { gin::kEmbedderNativeGin };
 
 double GetMonotonicSeconds() {
-  const double kMicrosecondsPerSecond = 1000000;
-  return static_cast<double>(mojo::GetTimeTicksNow()) / kMicrosecondsPerSecond;
+  return static_cast<double>(mojo::GetTimeTicksNow()) / base::Time::kMicrosecondsPerSecond;

[darin (slow to review), 2014/10/09 17:12:50]

nit: need to reformat for 80 character line limit

[prashant.hiremath, 2014/10/09 17:44:40]

I,m confused between moving second part i.e base::Time::kMicrosecondsPerSecond
to next line or using namespace base::Time; and keeping 2nd part as previous.
Which one would you think better? 

 }
 
 }  // namespace
 
 const char MonotonicClock::kModuleName[] = "monotonic_clock";
 
 v8::Local<v8::Value> MonotonicClock::GetModule(v8::Isolate* isolate) {
   gin::PerIsolateData* data = gin::PerIsolateData::From(isolate);
   v8::Local<v8::ObjectTemplate> templ =
       data->GetObjectTemplate(&g_wrapper_info);
   if (templ.IsEmpty()) {
     templ = gin::ObjectTemplateBuilder(isolate)
         .SetMethod("seconds", GetMonotonicSeconds)
         .Build();
     data->SetObjectTemplate(&g_wrapper_info, templ);
   }
   return templ->NewInstance();
 }
 
 }  // namespace apps
 }  // namespace mojo