[Impeller] dont accidentally copy shared ptr. (#49731)

Copying the shared ptr when we don't need to results in us incrementing/decrementing the ref count which isn't free.

Author: jonahwilliams

impeller/entity/contents/solid_color_contents.cc

@@ -7,6 +7,7 @@
 #include "impeller/entity/contents/clip_contents.h"
 #include "impeller/entity/contents/content_context.h"
 #include "impeller/entity/entity.h"
+#include "impeller/entity/geometry/geometry.h"
 #include "impeller/geometry/path.h"
 #include "impeller/renderer/render_pass.h"
 
@@ -38,7 +39,7 @@ std::optional<Rect> SolidColorContents::GetCoverage(
     return std::nullopt;
   }
 
-  auto geometry = GetGeometry();
+  const std::shared_ptr<Geometry>& geometry = GetGeometry();
   if (geometry == nullptr) {
     return std::nullopt;
   }

impeller/entity/contents/vertices_contents.cc

@@ -6,6 +6,8 @@
 
 #include "impeller/entity/contents/content_context.h"
 #include "impeller/entity/contents/filters/color_filter_contents.h"
+#include "impeller/entity/geometry/geometry.h"
+#include "impeller/entity/geometry/vertices_geometry.h"
 #include "impeller/entity/position_color.vert.h"
 #include "impeller/entity/vertices.frag.h"
 #include "impeller/geometry/color.h"
@@ -122,7 +124,7 @@ bool VerticesUVContents::Render(const ContentContext& renderer,
   Command cmd;
   DEBUG_COMMAND_INFO(cmd, "VerticesUV");
   auto& host_buffer = renderer.GetTransientsBuffer();
-  auto geometry = parent_.GetGeometry();
+  const std::shared_ptr<Geometry>& geometry = parent_.GetGeometry();
 
   auto coverage = src_contents->GetCoverage(Entity{});
   if (!coverage.has_value()) {
@@ -176,7 +178,7 @@ bool VerticesColorContents::Render(const ContentContext& renderer,
   Command cmd;
   DEBUG_COMMAND_INFO(cmd, "VerticesColors");
   auto& host_buffer = renderer.GetTransientsBuffer();
-  auto geometry = parent_.GetGeometry();
+  const std::shared_ptr<VerticesGeometry>& geometry = parent_.GetGeometry();
 
   auto geometry_result =
       geometry->GetPositionColorBuffer(renderer, entity, pass);

impeller/entity/geometry/round_rect_geometry.cc

@@ -2,12 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include <algorithm>
-
 #include "flutter/impeller/entity/geometry/round_rect_geometry.h"
 
-#include "flutter/impeller/entity/geometry/line_geometry.h"
-
 namespace impeller {
 
 RoundRectGeometry::RoundRectGeometry(const Rect& bounds, const Size& radii)