Reverts "[Impeller] Speed up vulkan startup time by re-using existing vulkan context. (flutter#166784)" (flutter#166938)

<!-- start_original_pr_link -->
Reverts: flutter#166784
<!-- end_original_pr_link -->
<!-- start_initiating_author -->
Initiated by: jonahwilliams
<!-- end_initiating_author -->
<!-- start_revert_reason -->
Reason for reverting: didn't do enough, going to try something
different.
<!-- end_revert_reason -->
<!-- start_original_pr_author -->
Original PR Author: jonahwilliams
<!-- end_original_pr_author -->

<!-- start_reviewers -->
Reviewed By: {matanlurey}
<!-- end_reviewers -->

<!-- start_revert_body -->
This change reverts the following previous change:
Once we've created the Vulkan context, lets just use it - creating it
isn't free. See numbers. Also change AHB swapchain to lazily create
images, which will also improve startup and will be added to an opt in
list to test startup performance.

```
════════════════════════════╡ ••• Raw results ••• ╞═════════════════════════════

timeToFirstFrameMicros:
  A:	371525.00	225155.00	
  B:	254054.00	254668.00	
timeToFirstFrameRasterizedMicros:
  A:	781015.00	555791.00	
  B:	527163.00	526827.00	



═════════════════════════╡ ••• Final A/B results ••• ╞══════════════════════════

Score	            Average A (noise)	Average B (noise)	Speed-up
timeToFirstFrameMicros	298340.00 (24.53%)	254361.00 (0.12%)	1.17x	
timeToFirstFrameRasterizedMicros	668403.00 (16.85%)	526995.00 (0.03%)	1.27x	
```
<!-- end_revert_body -->

Co-authored-by: auto-submit[bot] <flutter-engprod-team@google.com>

Author: auto-submit[bot]

engine/src/flutter/impeller/renderer/backend/vulkan/swapchain/ahb/ahb_swapchain_impl_vk.cc

@@ -68,9 +68,11 @@ std::shared_ptr<AHBSwapchainImplVK> AHBSwapchainImplVK::Create(
     std::weak_ptr<android::SurfaceControl> surface_control,
     const CreateTransactionCB& cb,
     const ISize& size,
-    bool enable_msaa) {
-  auto impl = std::shared_ptr<AHBSwapchainImplVK>(new AHBSwapchainImplVK(
-      context, std::move(surface_control), cb, size, enable_msaa));
+    bool enable_msaa,
+    size_t swapchain_image_count) {
+  auto impl = std::shared_ptr<AHBSwapchainImplVK>(
+      new AHBSwapchainImplVK(context, std::move(surface_control), cb, size,
+                             enable_msaa, swapchain_image_count));
   return impl->IsValid() ? impl : nullptr;
 }
 
@@ -79,10 +81,12 @@ AHBSwapchainImplVK::AHBSwapchainImplVK(
     std::weak_ptr<android::SurfaceControl> surface_control,
     const CreateTransactionCB& cb,
     const ISize& size,
-    bool enable_msaa)
+    bool enable_msaa,
+    size_t swapchain_image_count)
     : surface_control_(std::move(surface_control)), cb_(cb) {
   desc_ = android::HardwareBufferDescriptor::MakeForSwapchainImage(size);
-  pool_ = std::make_shared<AHBTexturePoolVK>(context, desc_);
+  pool_ =
+      std::make_shared<AHBTexturePoolVK>(context, desc_, swapchain_image_count);
   if (!pool_->IsValid()) {
     return;
   }

engine/src/flutter/impeller/renderer/backend/vulkan/swapchain/ahb/ahb_swapchain_impl_vk.h

@@ -73,7 +73,8 @@ class AHBSwapchainImplVK final
       std::weak_ptr<android::SurfaceControl> surface_control,
       const CreateTransactionCB& cb,
       const ISize& size,
-      bool enable_msaa);
+      bool enable_msaa,
+      size_t swapchain_image_count);
 
   ~AHBSwapchainImplVK();
 
@@ -136,7 +137,8 @@ class AHBSwapchainImplVK final
       std::weak_ptr<android::SurfaceControl> surface_control,
       const CreateTransactionCB& cb,
       const ISize& size,
-      bool enable_msaa);
+      bool enable_msaa,
+      size_t swapchain_image_count);
 
   bool Present(const std::shared_ptr<AHBTextureSourceVK>& texture);
 

engine/src/flutter/impeller/renderer/backend/vulkan/swapchain/ahb/ahb_swapchain_vk.cc

@@ -20,13 +20,27 @@ bool AHBSwapchainVK::IsAvailableOnPlatform() {
 AHBSwapchainVK::AHBSwapchainVK(const std::shared_ptr<Context>& context,
                                ANativeWindow* window,
                                const CreateTransactionCB& cb,
+                               const vk::UniqueSurfaceKHR& surface,
                                const ISize& size,
                                bool enable_msaa)
     : context_(context),
       surface_control_(
           std::make_shared<android::SurfaceControl>(window, "ImpellerSurface")),
       enable_msaa_(enable_msaa),
       cb_(cb) {
+  const auto [caps_result, surface_caps] =
+      ContextVK::Cast(*context).GetPhysicalDevice().getSurfaceCapabilitiesKHR(
+          *surface);
+  if (caps_result == vk::Result::eSuccess) {
+    swapchain_image_count_ =
+        std::clamp(surface_caps.minImageCount + 1u,  // preferred image count
+                   surface_caps.minImageCount,       // min count cannot be zero
+                   surface_caps.maxImageCount == 0u
+                       ? surface_caps.minImageCount + 1u
+                       : surface_caps.maxImageCount  // max zero means no limit
+        );
+  }
+
   UpdateSurfaceSize(size);
 }
 
@@ -66,11 +80,12 @@ void AHBSwapchainVK::UpdateSurfaceSize(const ISize& size) {
     return;
   }
   TRACE_EVENT0("impeller", __FUNCTION__);
-  auto impl = AHBSwapchainImplVK::Create(context_,          //
-                                         surface_control_,  //
-                                         cb_,               //
-                                         size,              //
-                                         enable_msaa_       //
+  auto impl = AHBSwapchainImplVK::Create(context_,               //
+                                         surface_control_,       //
+                                         cb_,                    //
+                                         size,                   //
+                                         enable_msaa_,           //
+                                         swapchain_image_count_  //
   );
   if (!impl || !impl->IsValid()) {
     VALIDATION_LOG << "Could not resize swapchain to size: " << size;

engine/src/flutter/impeller/renderer/backend/vulkan/swapchain/ahb/ahb_swapchain_vk.h

@@ -59,12 +59,14 @@ class AHBSwapchainVK final : public SwapchainVK {
   std::weak_ptr<Context> context_;
   std::shared_ptr<android::SurfaceControl> surface_control_;
   const bool enable_msaa_;
+  size_t swapchain_image_count_ = 3u;
   CreateTransactionCB cb_;
   std::shared_ptr<AHBSwapchainImplVK> impl_;
 
   explicit AHBSwapchainVK(const std::shared_ptr<Context>& context,
                           ANativeWindow* window,
                           const CreateTransactionCB& cb,
+                          const vk::UniqueSurfaceKHR& surface,
                           const ISize& size,
                           bool enable_msaa);
 };

engine/src/flutter/impeller/renderer/backend/vulkan/swapchain/ahb/ahb_texture_pool_vk.cc

@@ -9,19 +9,20 @@
 namespace impeller {
 
 AHBTexturePoolVK::AHBTexturePoolVK(std::weak_ptr<Context> context,
-                                   android::HardwareBufferDescriptor desc)
-    : context_(std::move(context)), desc_(desc) {
+                                   android::HardwareBufferDescriptor desc,
+                                   size_t max_entries)
+    : context_(std::move(context)), desc_(desc), max_entries_(max_entries) {
   if (!desc_.IsAllocatable()) {
     VALIDATION_LOG << "Swapchain image is not allocatable.";
     return;
   }
-  // Create at least one swapchain image to validate the allocation
-  // can succeed.
-  std::shared_ptr<AHBTextureSourceVK> texture = CreateTexture();
-  if (!texture->IsValid()) {
-    return;
+  for (auto i = 0u; i < max_entries_; i++) {
+    auto texture = CreateTexture();
+    if (!texture->IsValid()) {
+      return;
+    }
+    pool_.emplace_back(std::move(texture));
   }
-  pool_.emplace_back(std::move(texture));
   is_valid_ = true;
 }
 
@@ -48,6 +49,7 @@ void AHBTexturePoolVK::Push(std::shared_ptr<AHBTextureSourceVK> texture,
   }
   Lock lock(pool_mutex_);
   pool_.push_back(PoolEntry{std::move(texture), std::move(render_ready_fence)});
+  PerformGCLocked();
 }
 
 std::shared_ptr<AHBTextureSourceVK> AHBTexturePoolVK::CreateTexture() const {
@@ -77,6 +79,21 @@ std::shared_ptr<AHBTextureSourceVK> AHBTexturePoolVK::CreateTexture() const {
   return ahb_texture_source;
 }
 
+void AHBTexturePoolVK::PerformGC() {
+  Lock lock(pool_mutex_);
+  PerformGCLocked();
+}
+
+void AHBTexturePoolVK::PerformGCLocked() {
+  while (!pool_.empty() && (pool_.size() > max_entries_)) {
+    // Buffers are pushed to the back of the queue and popped from the front.
+    // The ones at the back should be given the most time for their fences to
+    // signal. If we are going to get rid of textures, they might as well be the
+    // newest ones since their fences will take the longest to signal.
+    pool_.pop_back();
+  }
+}
+
 bool AHBTexturePoolVK::IsValid() const {
   return is_valid_;
 }

engine/src/flutter/impeller/renderer/backend/vulkan/swapchain/ahb/ahb_texture_pool_vk.h

@@ -53,7 +53,8 @@ class AHBTexturePoolVK {
   ///                            in the pool.
   ///
   explicit AHBTexturePoolVK(std::weak_ptr<Context> context,
-                            android::HardwareBufferDescriptor desc);
+                            android::HardwareBufferDescriptor desc,
+                            size_t max_entries = 3u);
 
   ~AHBTexturePoolVK();
 
@@ -96,13 +97,24 @@ class AHBTexturePoolVK {
   void Push(std::shared_ptr<AHBTextureSourceVK> texture,
             fml::UniqueFD render_ready_fence);
 
+  //----------------------------------------------------------------------------
+  /// @brief      Perform an explicit GC of the pool items. This happens
+  ///             implicitly when a texture source us pushed into the pool but
+  ///             one may be necessary explicitly if there is no push back into
+  ///             the pool for a long time.
+  ///
+  void PerformGC();
+
  private:
   const std::weak_ptr<Context> context_;
   const android::HardwareBufferDescriptor desc_;
+  const size_t max_entries_;
   bool is_valid_ = false;
   Mutex pool_mutex_;
   std::deque<PoolEntry> pool_ IPLR_GUARDED_BY(pool_mutex_);
 
+  void PerformGCLocked() IPLR_REQUIRES(pool_mutex_);
+
   std::shared_ptr<AHBTextureSourceVK> CreateTexture() const;
 };
 

engine/src/flutter/impeller/renderer/backend/vulkan/swapchain/swapchain_vk.cc

@@ -45,6 +45,17 @@ std::shared_ptr<SwapchainVK> SwapchainVK::Create(
     return nullptr;
   }
 
+  vk::AndroidSurfaceCreateInfoKHR surface_info;
+  surface_info.setWindow(window.GetHandle());
+  auto [result, surface] =
+      ContextVK::Cast(*context).GetInstance().createAndroidSurfaceKHRUnique(
+          surface_info);
+  if (result != vk::Result::eSuccess) {
+    VALIDATION_LOG << "Could not create KHR Android Surface: "
+                   << vk::to_string(result);
+    return nullptr;
+  }
+
   // Use AHB Swapchains if they are opted in.
   if (ContextVK::Cast(*context).GetShouldEnableSurfaceControlSwapchain() &&
       AHBSwapchainVK::IsAvailableOnPlatform() &&
@@ -54,6 +65,7 @@ std::shared_ptr<SwapchainVK> SwapchainVK::Create(
         context,             //
         window.GetHandle(),  //
         cb,                  //
+        surface,             //
         window.GetSize(),    //
         enable_msaa          //
         ));
@@ -66,17 +78,6 @@ std::shared_ptr<SwapchainVK> SwapchainVK::Create(
     }
   }
 
-  vk::AndroidSurfaceCreateInfoKHR surface_info;
-  surface_info.setWindow(window.GetHandle());
-  auto [result, surface] =
-      ContextVK::Cast(*context).GetInstance().createAndroidSurfaceKHRUnique(
-          surface_info);
-  if (result != vk::Result::eSuccess) {
-    VALIDATION_LOG << "Could not create KHR Android Surface: "
-                   << vk::to_string(result);
-    return nullptr;
-  }
-
   // Fallback to KHR swapchains if AHB swapchains aren't available.
   return Create(context, std::move(surface), window.GetSize(), enable_msaa);
 }

engine/src/flutter/shell/platform/android/android_shell_holder.cc

@@ -21,7 +21,6 @@
 #include "flutter/shell/common/rasterizer.h"
 #include "flutter/shell/common/run_configuration.h"
 #include "flutter/shell/common/thread_host.h"
-#include "flutter/shell/platform/android/android_context_vk_impeller.h"
 #include "flutter/shell/platform/android/android_display.h"
 #include "flutter/shell/platform/android/android_image_generator.h"
 #include "flutter/shell/platform/android/android_rendering_selector.h"
@@ -83,8 +82,7 @@ static PlatformData GetDefaultPlatformData() {
 AndroidShellHolder::AndroidShellHolder(
     const flutter::Settings& settings,
     std::shared_ptr<PlatformViewAndroidJNI> jni_facade,
-    AndroidRenderingAPI android_rendering_api,
-    std::unique_ptr<AndroidContextVKImpeller> android_vk_context)
+    AndroidRenderingAPI android_rendering_api)
     : settings_(settings),
       jni_facade_(jni_facade),
       android_rendering_api_(android_rendering_api) {
@@ -115,18 +113,14 @@ AndroidShellHolder::AndroidShellHolder(
 
   fml::WeakPtr<PlatformViewAndroid> weak_platform_view;
   AndroidRenderingAPI rendering_api = android_rendering_api_;
-  std::shared_ptr<AndroidContextVKImpeller> shared_vk_context =
-      std::move(android_vk_context);
   Shell::CreateCallback<PlatformView> on_create_platform_view =
-      [&jni_facade, &weak_platform_view, rendering_api,
-       shared_vk_context](Shell& shell) {
+      [&jni_facade, &weak_platform_view, rendering_api](Shell& shell) {
         std::unique_ptr<PlatformViewAndroid> platform_view_android;
         platform_view_android = std::make_unique<PlatformViewAndroid>(
             shell,                   // delegate
             shell.GetTaskRunners(),  // task runners
             jni_facade,              // JNI interop
-            rendering_api,           // rendering API
-            shared_vk_context        // android vk
+            rendering_api            // rendering API
         );
         weak_platform_view = platform_view_android->GetWeakPtr();
         return platform_view_android;

engine/src/flutter/shell/platform/android/android_shell_holder.h

@@ -15,7 +15,6 @@
 #include "flutter/shell/platform/android/apk_asset_provider.h"
 #include "flutter/shell/platform/android/jni/platform_view_android_jni.h"
 #include "flutter/shell/platform/android/platform_view_android.h"
-#include "shell/platform/android/android_context_vk_impeller.h"
 
 namespace flutter {
 
@@ -38,11 +37,9 @@ namespace flutter {
 ///
 class AndroidShellHolder {
  public:
-  AndroidShellHolder(
-      const flutter::Settings& settings,
-      std::shared_ptr<PlatformViewAndroidJNI> jni_facade,
-      AndroidRenderingAPI android_rendering_api,
-      std::unique_ptr<AndroidContextVKImpeller> android_vk_context = nullptr);
+  AndroidShellHolder(const flutter::Settings& settings,
+                     std::shared_ptr<PlatformViewAndroidJNI> jni_facade,
+                     AndroidRenderingAPI android_rendering_api);
 
   ~AndroidShellHolder();
 

engine/src/flutter/shell/platform/android/android_shell_holder_unittests.cc

@@ -146,7 +146,7 @@ TEST(AndroidShellHolder, Create) {
   settings.enable_software_rendering = false;
   auto jni = std::make_shared<MockPlatformViewAndroidJNI>();
   auto holder = std::make_unique<AndroidShellHolder>(
-      settings, jni, AndroidRenderingAPI::kImpellerOpenGLES, nullptr);
+      settings, jni, AndroidRenderingAPI::kImpellerOpenGLES);
   EXPECT_NE(holder.get(), nullptr);
   EXPECT_TRUE(holder->IsValid());
   EXPECT_NE(holder->GetPlatformView().get(), nullptr);
@@ -160,7 +160,7 @@ TEST(AndroidShellHolder, HandlePlatformMessage) {
   settings.enable_software_rendering = false;
   auto jni = std::make_shared<MockPlatformViewAndroidJNI>();
   auto holder = std::make_unique<AndroidShellHolder>(
-      settings, jni, AndroidRenderingAPI::kImpellerOpenGLES, nullptr);
+      settings, jni, AndroidRenderingAPI::kImpellerOpenGLES);
   EXPECT_NE(holder.get(), nullptr);
   EXPECT_TRUE(holder->IsValid());
   EXPECT_NE(holder->GetPlatformView().get(), nullptr);