[Impeller] Add present wait latch. (#47311)

It turns out the fixing #47249 revealed further bugs: we were actually overwriting previous presents and dropping frames, which was what the forward progress error was hinting. Once this problem is fixed, we started hitting present timeouts or overdraw of swapchain images.

The fix for this is that we shouldn't even ask for a swapchain image until after we've called present, which actually wasn't tracked with anything.

The error:

```
A Dart VM Service on Pixel 6 Pro is available at: http://127.0.0.1:62491/_N4PSEPUtA0=/
The Flutter DevTools debugger and profiler on Pixel 6 Pro is available at: http://127.0.0.1:9102?uri=http://127.0.0.1:62491/_N4PSEPUtA0=/
W/OnBackInvokedCallback(19160): OnBackInvokedCallback is not enabled for the application.
W/OnBackInvokedCallback(19160): Set 'android:enableOnBackInvokedCallback="true"' in the application manifest.
W/vulkan  (19160): dequeueBuffer timed out: Function not implemented (-38)
E/flutter (19160): [ERROR:flutter/impeller/base/validation.cc(49)] Break on 'ImpellerValidationBreak' to inspect point of failure: Could not acquire next swapchain image: Timeout
E/flutter (19160): [ERROR:flutter/shell/gpu/gpu_surface_vulkan_impeller.cc(64)] No surface available.
```

Author: Jonah Williams

impeller/renderer/backend/vulkan/swapchain_impl_vk.cc

@@ -4,6 +4,7 @@
 
 #include "impeller/renderer/backend/vulkan/swapchain_impl_vk.h"
 
+#include "fml/synchronization/count_down_latch.h"
 #include "impeller/base/validation.h"
 #include "impeller/renderer/backend/vulkan/command_buffer_vk.h"
 #include "impeller/renderer/backend/vulkan/command_encoder_vk.h"
@@ -29,6 +30,9 @@ struct FrameSynchronizer {
   vk::UniqueSemaphore render_ready;
   vk::UniqueSemaphore present_ready;
   std::shared_ptr<CommandBuffer> final_cmd_buffer;
+  /// @brief A latch that is signaled _after_ a given swapchain image is
+  ///        presented.
+  std::shared_ptr<fml::CountDownLatch> present_latch;
   bool is_valid = false;
 
   explicit FrameSynchronizer(const vk::Device& device) {
@@ -45,12 +49,14 @@ struct FrameSynchronizer {
     acquire = std::move(acquire_res.value);
     render_ready = std::move(render_res.value);
     present_ready = std::move(present_res.value);
+    present_latch = std::make_shared<fml::CountDownLatch>(0u);
     is_valid = true;
   }
 
   ~FrameSynchronizer() = default;
 
   bool WaitForFence(const vk::Device& device) {
+    present_latch->Wait();
     if (auto result = device.waitForFences(
             *acquire,                             // fence
             true,                                 // wait all
@@ -65,6 +71,7 @@ struct FrameSynchronizer {
       VALIDATION_LOG << "Could not reset fence: " << vk::to_string(result);
       return false;
     }
+    present_latch = std::make_shared<fml::CountDownLatch>(1u);
     return true;
   }
 };
@@ -497,7 +504,10 @@ bool SwapchainImplVK::Present(const std::shared_ptr<SwapchainImageVK>& image,
     present_info.setImageIndices(indices);
     present_info.setWaitSemaphores(*sync->present_ready);
 
-    switch (auto result = present_queue_.presentKHR(present_info)) {
+    auto result = present_queue_.presentKHR(present_info);
+    sync->present_latch->CountDown();
+
+    switch (result) {
       case vk::Result::eErrorOutOfDateKHR:
         // Caller will recreate the impl on acquisition, not submission.
         [[fallthrough]];