[Impeller] remove shared_ptr copy/release in main rendering loop.

impeller/aiks/picture.cc

@@ -53,7 +53,7 @@ std::shared_ptr<Texture> Picture::RenderToTexture(
 
   // This texture isn't host visible, but we might want to add host visible
   // features to Image someday.
-  auto impeller_context = context.GetContext();
+  const std::shared_ptr<Context>& impeller_context = context.GetContext();
   // Do not use the render target cache as the lifecycle of this texture
   // will outlive a particular frame.
   RenderTargetAllocator render_target_allocator =

impeller/entity/contents/clip_contents.cc

@@ -125,7 +125,6 @@ bool ClipContents::Render(const ContentContext& renderer,
   options.primitive_type = geometry_result.type;
   pass.SetPipeline(renderer.GetClipPipeline(options));
 
-  auto allocator = renderer.GetContext()->GetResourceAllocator();
   pass.SetVertexBuffer(std::move(geometry_result.vertex_buffer));
 
   info.mvp = geometry_result.transform;

impeller/entity/contents/content_context.cc

@@ -414,7 +414,7 @@ fml::StatusOr<RenderTarget> ContentContext::MakeSubpass(
     ISize texture_size,
     const SubpassCallback& subpass_callback,
     bool msaa_enabled) const {
-  std::shared_ptr<Context> context = GetContext();
+  const std::shared_ptr<Context>& context = GetContext();
   RenderTarget subpass_target;
   if (context->GetCapabilities()->SupportsOffscreenMSAA() && msaa_enabled) {
     subpass_target = RenderTarget::CreateOffscreenMSAA(
@@ -438,7 +438,7 @@ fml::StatusOr<RenderTarget> ContentContext::MakeSubpass(
     const std::string& label,
     const RenderTarget& subpass_target,
     const SubpassCallback& subpass_callback) const {
-  std::shared_ptr<Context> context = GetContext();
+  const std::shared_ptr<Context>& context = GetContext();
 
   auto subpass_texture = subpass_target.GetRenderTargetTexture();
   if (!subpass_texture) {

impeller/entity/contents/runtime_effect_contents.cc

@@ -16,6 +16,7 @@
 #include "impeller/entity/contents/clip_contents.h"
 #include "impeller/entity/contents/content_context.h"
 #include "impeller/entity/runtime_effect.vert.h"
+#include "impeller/renderer/capabilities.h"
 #include "impeller/renderer/pipeline_library.h"
 #include "impeller/renderer/render_pass.h"
 #include "impeller/renderer/shader_function.h"
@@ -68,8 +69,8 @@ static std::shared_ptr<ShaderMetadata> MakeShaderMetadata(
 bool RuntimeEffectContents::Render(const ContentContext& renderer,
                                    const Entity& entity,
                                    RenderPass& pass) const {
-  auto context = renderer.GetContext();
-  auto library = context->GetShaderLibrary();
+  const std::shared_ptr<Context>& context = renderer.GetContext();
+  const std::shared_ptr<ShaderLibrary>& library = context->GetShaderLibrary();
 
   //--------------------------------------------------------------------------
   /// Get or register shader.
@@ -138,7 +139,7 @@ bool RuntimeEffectContents::Render(const ContentContext& renderer,
   /// layouts are known from the uniforms.
   ///
 
-  const auto& caps = context->GetCapabilities();
+  const std::shared_ptr<const Capabilities>& caps = context->GetCapabilities();
   const auto color_attachment_format = caps->GetDefaultColorFormat();
   const auto stencil_attachment_format = caps->GetDefaultStencilFormat();
 

impeller/entity/entity_pass.cc

@@ -249,7 +249,7 @@ static EntityPassTarget CreateRenderTarget(ContentContext& renderer,
                                            ISize size,
                                            int mip_count,
                                            const Color& clear_color) {
-  auto context = renderer.GetContext();
+  const std::shared_ptr<Context>& context = renderer.GetContext();
 
   /// All of the load/store actions are managed by `InlinePassContext` when
   /// `RenderPasses` are created, so we just set them to `kDontCare` here.
@@ -843,7 +843,7 @@ bool EntityPass::OnRender(
         collapsed_parent_pass) const {
   TRACE_EVENT0("impeller", "EntityPass::OnRender");
 
-  auto context = renderer.GetContext();
+  const std::shared_ptr<Context>& context = renderer.GetContext();
   InlinePassContext pass_context(context, pass_target,
                                  GetTotalPassReads(renderer), GetElementCount(),
                                  collapsed_parent_pass);

impeller/runtime_stage/runtime_stage_playground.cc

@@ -20,7 +20,8 @@ RuntimeStagePlayground::~RuntimeStagePlayground() = default;
 bool RuntimeStagePlayground::RegisterStage(const RuntimeStage& stage) {
   std::promise<bool> registration;
   auto future = registration.get_future();
-  auto library = GetContext()->GetShaderLibrary();
+  const std::shared_ptr<ShaderLibrary>& library =
+      GetContext()->GetShaderLibrary();
   GetContext()->GetShaderLibrary()->RegisterFunction(
       stage.GetEntrypoint(), ToShaderStage(stage.GetShaderStage()),
       stage.GetCodeMapping(),