Bug 1221659 - Make fullscreen transition on Linux take the designed time. r=roc

--HG--
extra : source : 6188bec8397bc87d1b3b5820adf66fc424a0bc20

widget/gtk/nsWindow.cpp

@@ -10,6 +10,7 @@
 #include "mozilla/MiscEvents.h"
 #include "mozilla/MouseEvents.h"
 #include "mozilla/TextEvents.h"
+#include "mozilla/TimeStamp.h"
 #include "mozilla/TouchEvents.h"
 #include "mozilla/UniquePtrExtensions.h"
 #include <algorithm>
@@ -4911,8 +4912,8 @@ public:
                              uint16_t aDuration, nsIRunnable* aCallback,
                              FullscreenTransitionWindow* aWindow)
         : mStage(aStage)
-        , mStep(0)
-        , mTotalSteps(aDuration / sInterval)
+        , mStartTime(TimeStamp::Now())
+        , mDuration(TimeDuration::FromMilliseconds(aDuration))
         , mCallback(aCallback)
         , mWindow(aWindow) { }
 
@@ -4921,7 +4922,8 @@ public:
 
 private:
     nsIWidget::FullscreenTransitionStage mStage;
-    uint16_t mStep, mTotalSteps;
+    TimeStamp mStartTime;
+    TimeDuration mDuration;
     nsCOMPtr<nsIRunnable> mCallback;
     RefPtr<FullscreenTransitionWindow> mWindow;
 };
@@ -4929,15 +4931,19 @@ private:
 /* static */ gboolean
 FullscreenTransitionData::TimeoutCallback(gpointer aData)
 {
+    bool finishing = false;
     auto data = static_cast<FullscreenTransitionData*>(aData);
-    data->mStep++;
-    gdouble opacity = data->mStep / gdouble(data->mTotalSteps);
+    gdouble opacity = (TimeStamp::Now() - data->mStartTime) / data->mDuration;
+    if (opacity >= 1.0) {
+        opacity = 1.0;
+        finishing = true;
+    }
     if (data->mStage == nsIWidget::eAfterFullscreenToggle) {
         opacity = 1.0 - opacity;
     }
     gtk_window_set_opacity(GTK_WINDOW(data->mWindow->mWindow), opacity);
 
-    if (data->mStep != data->mTotalSteps) {
+    if (!finishing) {
         return TRUE;
     }
     NS_DispatchToMainThread(data->mCallback.forget());