Revert "Improve iOS PlatformViews to better handle thread merging. (#16935)"

This reverts commit f6b8eda.

Author: Chris Yang

ci/licenses_golden/licenses_flutter

@@ -592,8 +592,6 @@ FILE: ../../../flutter/shell/common/shell_io_manager.cc
 FILE: ../../../flutter/shell/common/shell_io_manager.h
 FILE: ../../../flutter/shell/common/shell_test.cc
 FILE: ../../../flutter/shell/common/shell_test.h
-FILE: ../../../flutter/shell/common/shell_test_external_view_embedder.cc
-FILE: ../../../flutter/shell/common/shell_test_external_view_embedder.h
 FILE: ../../../flutter/shell/common/shell_test_platform_view.cc
 FILE: ../../../flutter/shell/common/shell_test_platform_view.h
 FILE: ../../../flutter/shell/common/shell_test_platform_view_gl.cc

flow/embedded_views.h

@@ -253,18 +253,6 @@ class ExternalViewEmbedder {
   // This is called after submitting the embedder frame and the surface frame.
   virtual void FinishFrame();
 
-  // This should only be called after |SubmitFrame|.
-  // This method provides the embedder a way to do additional tasks after
-  // |SubmitFrame|. After invoking this method, the current task on the
-  // TaskRunner should end immediately.
-  //
-  // For example on the iOS embedder, threads are merged in this call.
-  // A new frame on the platform thread starts immediately. If the GPU thread
-  // still has some task running, there could be two frames being rendered
-  // concurrently, which causes undefined behaviors.
-  virtual void EndFrame(
-      fml::RefPtr<fml::RasterThreadMerger> raster_thread_merger) {}
-
   FML_DISALLOW_COPY_AND_ASSIGN(ExternalViewEmbedder);
 
 };  // ExternalViewEmbedder

shell/common/BUILD.gn

@@ -191,8 +191,6 @@ if (enable_unittests) {
       "pipeline_unittests.cc",
       "shell_test.cc",
       "shell_test.h",
-      "shell_test_external_view_embedder.cc",
-      "shell_test_external_view_embedder.h",
       "shell_test_platform_view.cc",
       "shell_test_platform_view.h",
       "shell_unittests.cc",

shell/common/animator_unittests.cc

@@ -55,7 +55,7 @@ TEST_F(ShellTest, VSyncTargetTime) {
           return ShellTestPlatformView::Create(
               shell, shell.GetTaskRunners(), vsync_clock,
               std::move(create_vsync_waiter),
-              ShellTestPlatformView::BackendType::kDefaultBackend, nullptr);
+              ShellTestPlatformView::BackendType::kDefaultBackend);
         },
         [](Shell& shell) {
           return std::make_unique<Rasterizer>(shell, shell.GetTaskRunners());

shell/common/rasterizer.cc

@@ -136,16 +136,6 @@ void Rasterizer::Draw(fml::RefPtr<Pipeline<flutter::LayerTree>> pipeline) {
     consume_result = PipelineConsumeResult::MoreAvailable;
   }
 
-  // Merging the thread as we know the next `Draw` should be run on the platform
-  // thread.
-  if (raster_status == RasterStatus::kResubmit) {
-    auto* external_view_embedder = surface_->GetExternalViewEmbedder();
-    // We know only the `external_view_embedder` can
-    // causes|RasterStatus::kResubmit|. Check to make sure.
-    FML_DCHECK(external_view_embedder != nullptr);
-    external_view_embedder->EndFrame(raster_thread_merger_);
-  }
-
   // Consume as many pipeline items as possible. But yield the event loop
   // between successive tries.
   switch (consume_result) {

shell/common/shell_test.cc

@@ -260,12 +260,9 @@ std::unique_ptr<Shell> ShellTest::CreateShell(Settings settings,
                      simulate_vsync);
 }
 
-std::unique_ptr<Shell> ShellTest::CreateShell(
-    Settings settings,
-    TaskRunners task_runners,
-    bool simulate_vsync,
-    std::shared_ptr<ShellTestExternalViewEmbedder>
-        shell_test_external_view_embedder) {
+std::unique_ptr<Shell> ShellTest::CreateShell(Settings settings,
+                                              TaskRunners task_runners,
+                                              bool simulate_vsync) {
   const auto vsync_clock = std::make_shared<ShellTestVsyncClock>();
   CreateVsyncWaiter create_vsync_waiter = [&]() {
     if (simulate_vsync) {
@@ -278,18 +275,17 @@ std::unique_ptr<Shell> ShellTest::CreateShell(
   };
   return Shell::Create(
       task_runners, settings,
-      [vsync_clock, &create_vsync_waiter,
-       shell_test_external_view_embedder](Shell& shell) {
+      [vsync_clock, &create_vsync_waiter](Shell& shell) {
         return ShellTestPlatformView::Create(
             shell, shell.GetTaskRunners(), vsync_clock,
             std::move(create_vsync_waiter),
-            ShellTestPlatformView::BackendType::kDefaultBackend,
-            shell_test_external_view_embedder);
+            ShellTestPlatformView::BackendType::kDefaultBackend);
       },
       [](Shell& shell) {
         return std::make_unique<Rasterizer>(shell, shell.GetTaskRunners());
       });
 }
+
 void ShellTest::DestroyShell(std::unique_ptr<Shell> shell) {
   DestroyShell(std::move(shell), GetTaskRunnersForFixture());
 }

shell/common/shell_test.h

@@ -15,7 +15,6 @@
 #include "flutter/lib/ui/window/platform_message.h"
 #include "flutter/shell/common/run_configuration.h"
 #include "flutter/shell/common/shell.h"
-#include "flutter/shell/common/shell_test_external_view_embedder.h"
 #include "flutter/shell/common/thread_host.h"
 #include "flutter/shell/common/vsync_waiters_test.h"
 #include "flutter/testing/elf_loader.h"
@@ -32,12 +31,9 @@ class ShellTest : public ThreadTest {
   Settings CreateSettingsForFixture();
   std::unique_ptr<Shell> CreateShell(Settings settings,
                                      bool simulate_vsync = false);
-  std::unique_ptr<Shell> CreateShell(
-      Settings settings,
-      TaskRunners task_runners,
-      bool simulate_vsync = false,
-      std::shared_ptr<ShellTestExternalViewEmbedder>
-          shell_test_external_view_embedder = nullptr);
+  std::unique_ptr<Shell> CreateShell(Settings settings,
+                                     TaskRunners task_runners,
+                                     bool simulate_vsync = false);
   void DestroyShell(std::unique_ptr<Shell> shell);
   void DestroyShell(std::unique_ptr<Shell> shell, TaskRunners task_runners);
   TaskRunners GetTaskRunnersForFixture();

shell/common/shell_test_external_view_embedder.cc

@@ -19,24 +19,20 @@ std::unique_ptr<ShellTestPlatformView> ShellTestPlatformView::Create(
     TaskRunners task_runners,
     std::shared_ptr<ShellTestVsyncClock> vsync_clock,
     CreateVsyncWaiter create_vsync_waiter,
-    BackendType backend,
-    std::shared_ptr<ShellTestExternalViewEmbedder>
-        shell_test_external_view_embedder) {
+    BackendType backend) {
   // TODO(gw280): https://github.com/flutter/flutter/issues/50298
   // Make this fully runtime configurable
   switch (backend) {
     case BackendType::kDefaultBackend:
 #ifdef SHELL_ENABLE_GL
     case BackendType::kGLBackend:
       return std::make_unique<ShellTestPlatformViewGL>(
-          delegate, task_runners, vsync_clock, create_vsync_waiter,
-          shell_test_external_view_embedder);
+          delegate, task_runners, vsync_clock, create_vsync_waiter);
 #endif  // SHELL_ENABLE_GL
 #ifdef SHELL_ENABLE_VULKAN
     case BackendType::kVulkanBackend:
       return std::make_unique<ShellTestPlatformViewVulkan>(
-          delegate, task_runners, vsync_clock, create_vsync_waiter,
-          shell_test_external_view_embedder);
+          delegate, task_runners, vsync_clock, create_vsync_waiter);
 #endif  // SHELL_ENABLE_VULKAN
     default:
       FML_LOG(FATAL) << "No backends supported for ShellTestPlatformView";