[Impeller] reland: switch Pipeline to use raw ptr instead of shared ptr for recorded references. (flutter/engine#57086)

Prev: flutter/engine#57015

There is a unit test that is clearing out the pipeline storage, manually null out captured PipelineRef.

Author: Jonah Williams

engine/src/flutter/ci/licenses_golden/licenses_flutter

@@ -42962,6 +42962,8 @@ ORIGIN: ../../../flutter/impeller/core/platform.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/core/platform.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/core/range.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/core/range.h + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/core/raw_ptr.cc + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/core/raw_ptr.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/core/resource_binder.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/core/resource_binder.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/core/runtime_types.cc + ../../../flutter/LICENSE
@@ -45891,6 +45893,8 @@ FILE: ../../../flutter/impeller/core/platform.cc
 FILE: ../../../flutter/impeller/core/platform.h
 FILE: ../../../flutter/impeller/core/range.cc
 FILE: ../../../flutter/impeller/core/range.h
+FILE: ../../../flutter/impeller/core/raw_ptr.cc
+FILE: ../../../flutter/impeller/core/raw_ptr.h
 FILE: ../../../flutter/impeller/core/resource_binder.cc
 FILE: ../../../flutter/impeller/core/resource_binder.h
 FILE: ../../../flutter/impeller/core/runtime_types.cc

engine/src/flutter/impeller/core/BUILD.gn

@@ -23,6 +23,8 @@ impeller_component("core") {
     "platform.h",
     "range.cc",
     "range.h",
+    "raw_ptr.cc",
+    "raw_ptr.h",
     "resource_binder.cc",
     "resource_binder.h",
     "runtime_types.cc",

engine/src/flutter/impeller/core/raw_ptr.cc

@@ -0,0 +1,11 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "impeller/core/raw_ptr.h"
+
+namespace impeller {
+
+//
+
+}

engine/src/flutter/impeller/core/raw_ptr.h

@@ -0,0 +1,84 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef FLUTTER_IMPELLER_CORE_RAW_PTR_H_
+#define FLUTTER_IMPELLER_CORE_RAW_PTR_H_
+
+#include <memory>
+
+namespace impeller {
+
+/// @brief A wrapper around a raw ptr that adds additional unopt mode only
+/// checks.
+template <typename T>
+class raw_ptr {
+ public:
+  explicit raw_ptr(const std::shared_ptr<T>& ptr)
+      : ptr_(ptr.get())
+#if !NDEBUG
+        ,
+        weak_ptr_(ptr)
+#endif
+  {
+  }
+
+  raw_ptr() : ptr_(nullptr) {}
+
+  T* operator->() {
+#if !NDEBUG
+    FML_CHECK(weak_ptr_.lock());
+#endif
+    return ptr_;
+  }
+
+  const T* operator->() const {
+#if !NDEBUG
+    FML_CHECK(weak_ptr_.lock());
+#endif
+    return ptr_;
+  }
+
+  T* get() {
+#if !NDEBUG
+    FML_CHECK(weak_ptr_.lock());
+#endif
+    return ptr_;
+  }
+
+  T& operator*() {
+#if !NDEBUG
+    FML_CHECK(weak_ptr_.lock());
+#endif
+    return *ptr_;
+  }
+
+  const T& operator*() const {
+#if !NDEBUG
+    FML_CHECK(weak_ptr_.lock());
+#endif
+    return *ptr_;
+  }
+
+  template <class U>
+  inline bool operator==(raw_ptr<U> const& other) const {
+    return ptr_ == other.ptr_;
+  }
+
+  template <class U>
+  inline bool operator!=(raw_ptr<U> const& other) const {
+    return !(*this == other);
+  }
+
+  explicit operator bool() const { return !!ptr_; }
+
+ private:
+  T* ptr_;
+#if !NDEBUG
+  std::weak_ptr<T> weak_ptr_;
+#endif
+};
+
+}  // namespace impeller
+
+#endif  // FLUTTER_IMPELLER_CORE_RAW_PTR_H_

engine/src/flutter/impeller/entity/contents/color_source_contents.h

@@ -104,8 +104,7 @@ class ColorSourceContents : public Contents {
   using PipelineBuilderMethod = std::shared_ptr<Pipeline<PipelineDescriptor>> (
       impeller::ContentContext::*)(ContentContextOptions) const;
   using PipelineBuilderCallback =
-      std::function<std::shared_ptr<Pipeline<PipelineDescriptor>>(
-          ContentContextOptions)>;
+      std::function<PipelineRef(ContentContextOptions)>;
   using CreateGeometryCallback =
       std::function<GeometryResult(const ContentContext& renderer,
                                    const Entity& entity,

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

@@ -569,8 +569,7 @@ void ContentContext::SetWireframe(bool wireframe) {
   wireframe_ = wireframe;
 }
 
-std::shared_ptr<Pipeline<PipelineDescriptor>>
-ContentContext::GetCachedRuntimeEffectPipeline(
+PipelineRef ContentContext::GetCachedRuntimeEffectPipeline(
     const std::string& unique_entrypoint_name,
     const ContentContextOptions& options,
     const std::function<std::shared_ptr<Pipeline<PipelineDescriptor>>()>&
@@ -580,7 +579,7 @@ ContentContext::GetCachedRuntimeEffectPipeline(
   if (it == runtime_effect_pipelines_.end()) {
     it = runtime_effect_pipelines_.insert(it, {key, create_callback()});
   }
-  return it->second;
+  return raw_ptr(it->second);
 }
 
 void ContentContext::ClearCachedRuntimeEffectPipeline(