Merge pull request #220 from UnityTech/gif

Fix GIF memory overflow issue.

Author: kgdev

Runtime/ui/painting/codec_gif.cs

@@ -25,6 +25,7 @@ public class FrameData {
         volatile int _repetitionCount;
         volatile bool _isDone;
         volatile int _frameIndex;
+        volatile Texture2D _texture;
         readonly UIWidgetsCoroutine _coroutine;
 
         public GifCodec(byte[] bytes) {
@@ -129,20 +130,24 @@ public IPromise<FrameInfo> getNextFrame() {
             return frame.Then(frameData => {
                 this._nextFrame();
 
-                if (frameData.frameInfo != null) {
-                    return frameData.frameInfo;
+                if (this._texture == null) {
+                    this._texture = new Texture2D(this._width, this._height, TextureFormat.BGRA32, false);
+                    this._texture.hideFlags = HideFlags.HideAndDontSave;
                 }
 
-                var tex = new Texture2D(this._width, this._height, TextureFormat.BGRA32, false);
-                tex.hideFlags = HideFlags.HideAndDontSave;
+                var tex = this._texture;
                 tex.LoadRawTextureData(frameData.gifFrame.bytes);
                 tex.Apply();
 
+                if (frameData.frameInfo != null) {
+                    return frameData.frameInfo;
+                }
+
                 frameData.frameInfo = new FrameInfo {
                     image = new Image(tex),
                     duration = TimeSpan.FromMilliseconds(frameData.gifFrame.delay)
                 };
-                frameData.gifFrame = null; // dispose gifFrame
+                // frameData.gifFrame = null; // dispose gifFrame
 
                 return frameData.frameInfo;
             });