asABitmap is deprecated, switch over to (simpler) isABitmap

cc/raster/tile_task_worker_pool.cc

Index: cc/raster/tile_task_worker_pool.cc
diff --git a/cc/raster/tile_task_worker_pool.cc b/cc/raster/tile_task_worker_pool.cc
index 8829e2c6881681bcfc8e029f344988ffcdac2a87..05293fa7f3b6f59666542b83796b25773f208d33 100644
--- a/cc/raster/tile_task_worker_pool.cc
+++ b/cc/raster/tile_task_worker_pool.cc
@@ -161,14 +161,7 @@ class SkipImageFilter : public SkDrawFilter {
       return false;
 
     SkShader* shader = paint->getShader();
-    if (!shader)
-      return true;
-    SkShader::BitmapType bitmap_type =
-        shader->asABitmap(nullptr, nullptr, nullptr);
-    // The kDefault_BitmapType is returned for images. Other bitmap types are
-    // simply bitmap representations of colors such as gradients. So, we can
-    // return true and draw for any case except kDefault_BitmapType.
-    return bitmap_type != SkShader::kDefault_BitmapType;
+    return !shader || !shader->isABitmap();
   }
 };