Bug 552020. Part 3: Enable creation of mozilla::TimeStamp from system Timestamps. r=roc

widget/gonk/HwcComposer2D.cpp

@@ -231,7 +231,7 @@ HwcComposer2D::RunVsyncEventControl(bool aEnable)
 void
 HwcComposer2D::Vsync(int aDisplay, nsecs_t aVsyncTimestamp)
 {
-    TimeStamp vsyncTime = mozilla::TimeStamp(aVsyncTimestamp);
+    TimeStamp vsyncTime = mozilla::TimeStamp::FromSystemTime(aVsyncTimestamp);
     nsecs_t vsyncInterval = aVsyncTimestamp - mLastVsyncTime;
     if (vsyncInterval < 16000000 || vsyncInterval > 17000000) {
       LOGE("Non-uniform vsync interval: %lld\n", vsyncInterval);

widget/gonk/nsAppShell.cpp

@@ -715,7 +715,7 @@ GeckoInputDispatcher::notifyMotion(const NotifyMotionArgs* args)
     int32_t action = args->action & AMOTION_EVENT_ACTION_MASK;
     int touchCount = args->pointerCount;
     MOZ_ASSERT(touchCount <= MAX_POINTERS);
-    TimeStamp timestamp = TimeStamp(args->eventTime);
+    TimeStamp timestamp = mozilla::TimeStamp::FromSystemTime(args->eventTime);
     Modifiers modifiers = getDOMModifiers(args->metaState);
 
     MultiTouchInput::MultiTouchType touchType = MultiTouchInput::MULTITOUCH_CANCEL;

xpcom/ds/TimeStamp.h

@@ -387,11 +387,20 @@ public:
   MOZ_CONSTEXPR TimeStamp() : mValue(0) {}
   // Default copy-constructor and assignment are OK
 
-#ifdef MOZ_WIDGET_GONK
-  TimeStamp(int64_t aAndroidTime) : mValue(aAndroidTime)
+  /**
+   * The system timestamps are the same as the TimeStamp
+   * retrieved by mozilla::TimeStamp. Since we need this for
+   * vsync timestamps, we enable the creation of mozilla::TimeStamps
+   * on platforms that support vsync aligned refresh drivers / compositors
+   * Verified true as of Nov 7, 2014: B2G and OS X
+   * UNTESTED ON OTHER PLATFORMS
+   */
+#if defined(MOZ_WIDGET_GONK) || defined(MOZ_WIDGET_COCOA)
+  static TimeStamp FromSystemTime(int64_t aSystemTime)
   {
-    static_assert(sizeof(aAndroidTime) == sizeof(TimeStampValue),
-                  "Android timestamp should be same units as TimeStampValue");
+    static_assert(sizeof(aSystemTime) == sizeof(TimeStampValue),
+                  "System timestamp should be same units as TimeStampValue");
+    return TimeStamp(aSystemTime);
   }
 #endif