layout: Convert animated image delays < 10ms into 100 ms delays (#39189)

Some animated images in the wild have delays <10ms and browsers usually
change them into 100ms as such small timings are unusual.

Relevant code in FF:
https://searchfox.org/firefox-main/source/image/FrameTimeout.h#35

Testing: Manually tested
Fixes: #39187

Signed-off-by: sagudev <16504129+sagudev@users.noreply.github.com>

components/pixels/lib.rs

@@ -287,7 +287,20 @@ pub struct RasterImage {
     pub frames: Vec<ImageFrame>,
 }
 
-#[derive(Clone, Deserialize, MallocSizeOf, Serialize)]
+fn sensible_delay(delay: Duration) -> Duration {
+    // Very small timeout values are problematic for two reasons: we don't want
+    // to burn energy redrawing animated images extremely fast, and broken tools
+    // generate these values when they actually want a "default" value, so such
+    // images won't play back right without normalization.
+    // https://searchfox.org/firefox-main/rev/c79acad610ddbb31bd92e837e056b53716f5ccf2/image/FrameTimeout.h#35
+    if delay <= Duration::from_millis(10) {
+        Duration::from_millis(100)
+    } else {
+        delay
+    }
+}
+
+#[derive(Clone, Debug, Deserialize, MallocSizeOf, Serialize)]
 pub struct ImageFrame {
     pub delay: Option<Duration>,
     /// References a range of the `bytes` field from the image that this
@@ -297,6 +310,12 @@ pub struct ImageFrame {
     pub height: u32,
 }
 
+impl ImageFrame {
+    pub fn delay(&self) -> Option<Duration> {
+        self.delay.map(sensible_delay)
+    }
+}
+
 /// A non-owning reference to the data of an [ImageFrame]
 pub struct ImageFrameView<'a> {
     pub delay: Option<Duration>,
@@ -305,6 +324,12 @@ pub struct ImageFrameView<'a> {
     pub height: u32,
 }
 
+impl ImageFrameView<'_> {
+    pub fn delay(&self) -> Option<Duration> {
+        self.delay.map(sensible_delay)
+    }
+}
+
 impl RasterImage {
     pub fn should_animate(&self) -> bool {
         self.frames.len() > 1

components/shared/layout/lib.rs

@@ -661,7 +661,7 @@ impl ImageAnimationState {
                 .frames
                 .get(self.active_frame)
                 .unwrap()
-                .delay
+                .delay()
                 .unwrap()
                 .as_secs_f64();
         let mut next_active_frame_id = self.active_frame;
@@ -671,7 +671,7 @@ impl ImageAnimationState {
                 .frames
                 .get(next_active_frame_id)
                 .unwrap()
-                .delay
+                .delay()
                 .unwrap()
                 .as_secs_f64();
         }