Bug 1608131 - Remove unused native drawing filtering flags. r=aosmond

GOOD and LINEAR are basically the same and neither of them
is NEAREST.

Differential Revision: https://phabricator.services.mozilla.com/D59341

--HG--
extra : moz-landing-system : lando

gfx/thebes/gfxWindowsNativeDrawing.cpp

@@ -266,10 +266,7 @@ void gfxWindowsNativeDrawing::PaintToContext() {
 
       Rect rect(Point(0.0, 0.0), ToSize(mNativeRect.Size()));
       Matrix m = Matrix::Scaling(1.0 / mScale.width, 1.0 / mScale.height);
-      SamplingFilter filter = (mNativeDrawFlags & DO_NEAREST_NEIGHBOR_FILTERING)
-                                  ? SamplingFilter::LINEAR
-                                  : SamplingFilter::GOOD;
-      SurfacePattern pat(source, ExtendMode::CLAMP, m, filter);
+      SurfacePattern pat(source, ExtendMode::CLAMP, m);
       dt->FillRect(rect, pat);
     }
 

gfx/thebes/gfxWindowsNativeDrawing.h

@@ -31,11 +31,6 @@ class gfxWindowsNativeDrawing {
        using SetWorldTransform */
     CAN_COMPLEX_TRANSFORM = 1 << 2,
     CANNOT_COMPLEX_TRANSFORM = 0 << 2,
-
-    /* If we have to do transforms with cairo, should we use nearest-neighbour
-       filtering? */
-    DO_NEAREST_NEIGHBOR_FILTERING = 1 << 3,
-    DO_BILINEAR_FILTERING = 0 << 3
   };
 
   /* Create native win32 drawing for a rectangle bounded by
@@ -62,7 +57,7 @@ class gfxWindowsNativeDrawing {
                           uint32_t nativeDrawFlags =
                               CANNOT_DRAW_TO_COLOR_ALPHA |
                               CANNOT_AXIS_ALIGNED_SCALE |
-                              CANNOT_COMPLEX_TRANSFORM | DO_BILINEAR_FILTERING);
+                              CANNOT_COMPLEX_TRANSFORM);
 
   /* Returns a HDC which may be used for native drawing.  This HDC is valid
    * until EndNativeDrawing is called; if it is used for drawing after that