Fix rotated image filter shader (#180027)

fixes https://github.com/flutter/flutter/issues/179918

This blocks us from rerasterizing if there is a rotation on the
imagefilter being drawn. This restores the behavior before
c089837469
while keeping the golden introduced in that pr working.

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engine/src/flutter/impeller/display_list/aiks_dl_runtime_effect_unittests.cc

@@ -473,5 +473,56 @@ TEST_P(AiksTest, ClippedBackdropFilterWithShader) {
   ASSERT_TRUE(OpenPlaygroundHere(builder.Build()));
 }
 
+TEST_P(AiksTest, RuntimeEffectImageFilterRotated) {
+  auto image = DlImageImpeller::Make(CreateTextureForFixture("kalimba.jpg"));
+  auto size = image->GetBounds().GetSize();
+
+  struct FragUniforms {
+    Size size;
+  } frag_uniforms = {.size = Size(size.width, size.height)};
+  auto uniform_data = std::make_shared<std::vector<uint8_t>>();
+  uniform_data->resize(sizeof(FragUniforms));
+  memcpy(uniform_data->data(), &frag_uniforms, sizeof(FragUniforms));
+
+  auto runtime_stages_result = OpenAssetAsRuntimeStage("gradient.frag.iplr");
+  ABSL_ASSERT_OK(runtime_stages_result);
+  std::shared_ptr<RuntimeStage> runtime_stage =
+      runtime_stages_result
+          .value()[PlaygroundBackendToRuntimeStageBackend(GetBackend())];
+  ASSERT_TRUE(runtime_stage);
+  ASSERT_TRUE(runtime_stage->IsDirty());
+
+  std::vector<std::shared_ptr<DlColorSource>> sampler_inputs = {
+      nullptr,
+  };
+
+  auto runtime_filter = DlImageFilter::MakeRuntimeEffect(
+      DlRuntimeEffectImpeller::Make(runtime_stage), sampler_inputs,
+      uniform_data);
+
+  Scalar rotation = 45;
+
+  auto callback = [&]() -> sk_sp<DisplayList> {
+    if (AiksTest::ImGuiBegin("Controls", nullptr,
+                             ImGuiWindowFlags_AlwaysAutoResize)) {
+      ImGui::SliderFloat("rotation", &rotation, 0, 360);
+      ImGui::End();
+    }
+    DisplayListBuilder builder;
+    builder.Translate(size.width * 0.5, size.height * 0.5);
+    builder.Rotate(rotation);
+    builder.Translate(-size.width * 0.5, -size.height * 0.5);
+
+    DlPaint paint;
+    paint.setImageFilter(runtime_filter);
+    builder.DrawImage(image, DlPoint(0.0, 0.0),
+                      DlImageSampling::kNearestNeighbor, &paint);
+
+    return builder.Build();
+  };
+
+  ASSERT_TRUE(OpenPlaygroundHere(callback));
+}
+
 }  // namespace testing
 }  // namespace impeller

engine/src/flutter/impeller/renderer/snapshot.h

@@ -45,11 +45,15 @@ struct Snapshot {
   /// capture the padding.
   bool needs_rasterization_for_runtime_effects = false;
 
-  /// Any snapshot that is scaled should rerasterize because we should be
+  /// Any snapshot that is scaled should re-rasterize because we should be
   /// performing the RuntimeEffect at the resolution of the screen, not the
   /// scaled up or scaled down version of the snapshot.
   bool ShouldRasterizeForRuntimeEffects() const {
-    return !transform.IsTranslationOnly() ||
+    // If the transform has a rotation we don't re-rasterize because we'll lose
+    // the rotation.
+    // TODO(tbd): We should re-rasterize scaled and rotated snapshots.
+    return (!transform.IsTranslationOnly() &&
+            transform.IsTranslationScaleOnly()) ||
            needs_rasterization_for_runtime_effects;
   }