[Impeller] disable depth-stencil and MSAA for gaussian and downsample. (#165137)

Using MSAA w/ depth stencil requires extra work on the GPU to track
multiple samples and clear the depth/stencil textures.

See also:
https://docs.qualcomm.com/bundle/publicresource/topics/80-78185-2/best_practices.html

Its unclear _how_ much this matters, but adreno recommends minimizing
bin count and as such minimizing msaa samples. Well, we can fully
minimize it by not enabling it. Removing depth stencil was also
considered in the past, this should be removed as it requires us to
clear, which isn't free.

Its likely this won't have a huge performance impact, but seems like a
good best practice.

Author: Jonah Williams

engine/src/flutter/impeller/entity/contents/content_context.cc

@@ -307,6 +307,12 @@ ContentContext::ContentContext(
       .primitive_type = PrimitiveType::kTriangleStrip,
       .color_attachment_pixel_format =
           context_->GetCapabilities()->GetDefaultColorFormat()};
+  auto options_no_msaa_no_depth_stencil = ContentContextOptions{
+      .sample_count = SampleCount::kCount1,
+      .primitive_type = PrimitiveType::kTriangleStrip,
+      .color_attachment_pixel_format =
+          context_->GetCapabilities()->GetDefaultColorFormat(),
+      .has_depth_stencil_attachments = false};
   const auto supports_decal = static_cast<Scalar>(
       context_->GetCapabilities()->SupportsDecalSamplerAddressMode());
 
@@ -380,14 +386,14 @@ ContentContext::ContentContext(
     clip_pipelines_.SetDefault(
         options,
         std::make_unique<ClipPipeline>(*context_, clip_pipeline_descriptor));
-    texture_downsample_pipelines_.CreateDefault(*context_,
-                                                options_trianglestrip);
+    texture_downsample_pipelines_.CreateDefault(
+        *context_, options_no_msaa_no_depth_stencil);
     rrect_blur_pipelines_.CreateDefault(*context_, options_trianglestrip);
     texture_strict_src_pipelines_.CreateDefault(*context_, options);
     tiled_texture_pipelines_.CreateDefault(*context_, options,
                                            {supports_decal});
-    gaussian_blur_pipelines_.CreateDefault(*context_, options_trianglestrip,
-                                           {supports_decal});
+    gaussian_blur_pipelines_.CreateDefault(
+        *context_, options_no_msaa_no_depth_stencil, {supports_decal});
     border_mask_blur_pipelines_.CreateDefault(*context_, options_trianglestrip);
     color_matrix_color_filter_pipelines_.CreateDefault(*context_,
                                                        options_trianglestrip);

engine/src/flutter/impeller/entity/contents/filters/gaussian_blur_filter_contents.cc

@@ -377,7 +377,9 @@ fml::StatusOr<RenderTarget> MakeDownsampleSubpass(
           return pass.Draw().ok();
         };
     return renderer.MakeSubpass("Gaussian Blur Filter", pass_args.subpass_size,
-                                command_buffer, subpass_callback);
+                                command_buffer, subpass_callback,
+                                /*msaa_enabled=*/false,
+                                /*depth_stencil_enabled=*/false);
   } else {
     // This assumes we don't scale below 1/16.
     Scalar edge = 1.0;
@@ -446,7 +448,9 @@ fml::StatusOr<RenderTarget> MakeDownsampleSubpass(
           return pass.Draw().ok();
         };
     return renderer.MakeSubpass("Gaussian Blur Filter", pass_args.subpass_size,
-                                command_buffer, subpass_callback);
+                                command_buffer, subpass_callback,
+                                /*msaa_enabled=*/false,
+                                /*depth_stencil_enabled=*/false);
   }
 }
 
@@ -511,8 +515,9 @@ fml::StatusOr<RenderTarget> MakeBlurSubpass(
                                 destination_target.value(), command_buffer,
                                 subpass_callback);
   } else {
-    return renderer.MakeSubpass("Gaussian Blur Filter", subpass_size,
-                                command_buffer, subpass_callback);
+    return renderer.MakeSubpass(
+        "Gaussian Blur Filter", subpass_size, command_buffer, subpass_callback,
+        /*msaa_enabled=*/false, /*depth_stencil_enabled=*/false);
   }
 }