Fix microsoft#949

Author: zhengbli

baselines/dom.generated.d.ts

@@ -7071,7 +7071,7 @@ declare var IDBVersionChangeEvent: {
 }
 
 interface ImageData {
-    data: number[];
+    data: Uint8ClampedArray;
     height: number;
     width: number;
 }

baselines/webworker.generated.d.ts

@@ -460,7 +460,7 @@ declare var IDBVersionChangeEvent: {
 }
 
 interface ImageData {
-    data: number[];
+    data: Uint8ClampedArray;
     height: number;
     width: number;
 }

inputfiles/overridingTypes.json

@@ -205,5 +205,11 @@
             "new(width: number, height: number): ImageData",
             "new(array: Uint8ClampedArray, width: number, height: number): ImageData"
         ]
+    },
+    {
+        "kind": "property",
+        "interface": "ImageData",
+        "name": "data",
+        "type": "Uint8ClampedArray"
     }
 ]