Make context current on teardown

Normally, SkiaOutputSurfaceImplOnGpu is responsible for making a GL
context current before any calls into DirectContextProvider (e.g.
ImplOnGpu::CopyResult, ImplOnGpu::PerformDelayedWork, ~ImplOnGpu).

One exception to this is if there is an asynchronous GLRendererCopier
readback in flight as ~ImplOnGpu is called (e.g. for tab picker on
Android). Specifically, if either ReadPixelsWorkflow::Finish or
~ReadPixelsWorkflow has not been called yet.

This CL does 2 things:

1) It does a glFinish() to guaranteee that ReadPixelsWorkflow::Finish
   will be called before ~ImplOnGpu finishes. This may cause some jank,
   but it is the simplest method to avoid a leak of GPU resources for
   in flight readbacks.

2) It does a MakeCurrent in DirectContextProvider::Destroy to make sure
   that a context is current when ~GLPixelBufferRGBAResult is called
   (see [1]).

[1] https://cs.chromium.org/chromium/src/components/viz/service/display/gl_renderer_copier.cc?rcl=ec3242c55275c8f1c2ea6ac2a0211c391eba7ddc&l=543

Bug: 1020558
Change-Id: I5092594b879efaedd65f2ed9ee3fce297930d294
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1898126
Commit-Queue: Jonathan Backer <backer@chromium.org>
Reviewed-by: kylechar <kylechar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#712274}

components/viz/service/display_embedder/direct_context_provider.cc

@@ -96,6 +96,7 @@ DirectContextProvider::DirectContextProvider(
   command_buffer_ = std::move(command_buffer);
   decoder_ = std::move(decoder);
   gl_context_ = std::move(gl_context);
+  gl_surface_ = std::move(gl_surface);
 
   gles2_implementation_ = std::make_unique<gpu::gles2::GLES2Implementation>(
       gles2_cmd_helper_.get(), nullptr, transfer_buffer_.get(),
@@ -123,7 +124,11 @@ DirectContextProvider::~DirectContextProvider() {
 
 void DirectContextProvider::Destroy() {
   DCHECK(decoder_);
-  bool have_context = !decoder_->WasContextLost();
+
+  bool have_context = !decoder_->WasContextLost() &&
+                      (gl_context_->IsCurrent(nullptr) ||
+                       gl_context_->MakeCurrent(gl_surface_.get()));
+
   if (have_context && framebuffer_id_ != 0) {
     gles2_implementation_->DeleteFramebuffers(1, &framebuffer_id_);
     framebuffer_id_ = 0;
@@ -360,4 +365,9 @@ void DirectContextProvider::MarkContextLost() {
   }
 }
 
+void DirectContextProvider::FinishQueries() {
+  if (decoder_->HasPendingQueries())
+    gles2_implementation_->Finish();
+}
+
 }  // namespace viz

components/viz/service/display_embedder/direct_context_provider.h

@@ -102,6 +102,8 @@ class VIZ_SERVICE_EXPORT DirectContextProvider
   GLuint GenClientTextureId();
   void DeleteClientTextureId(GLuint client_id);
   void MarkContextLost();
+  // Call a glFinish() to complete any pending queries.
+  void FinishQueries();
 
   // ContextProvider implementation.
   void AddRef() const override;
@@ -172,6 +174,7 @@ class VIZ_SERVICE_EXPORT DirectContextProvider
   std::unique_ptr<gpu::gles2::GLES2Decoder> decoder_;
   std::unique_ptr<gpu::TransferBuffer> transfer_buffer_;
   scoped_refptr<gl::GLContext> gl_context_;
+  scoped_refptr<gl::GLSurface> gl_surface_;
   std::unique_ptr<gpu::gles2::GLES2Implementation> gles2_implementation_;
 
   GLuint framebuffer_id_ = 0;

components/viz/service/display_embedder/skia_output_surface_impl_on_gpu.cc

@@ -651,6 +651,8 @@ SkiaOutputSurfaceImplOnGpu::~SkiaOutputSurfaceImplOnGpu() {
   }
 
   if (copier_) {
+    context_provider_->FinishQueries();
+
     copier_ = nullptr;
     texture_deleter_ = nullptr;
     context_provider_ = nullptr;