Re-land^2 WebVR compositor bypass via BrowserMain context + mailbox

chrome/browser/android/vr_shell/vr_shell_command_buffer_gl.cc

Index: chrome/browser/android/vr_shell/vr_shell_command_buffer_gl.cc
diff --git a/chrome/browser/android/vr_shell/vr_shell_command_buffer_gl.cc b/chrome/browser/android/vr_shell/vr_shell_command_buffer_gl.cc
new file mode 100644
index 0000000000000000000000000000000000000000..4b1e1d54919420b166c7f544099fe9de4e0e70b5
--- /dev/null
+++ b/chrome/browser/android/vr_shell/vr_shell_command_buffer_gl.cc
@@ -0,0 +1,146 @@
+// Copyright 2017 The Chromium 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 "chrome/browser/android/vr_shell/vr_shell_command_buffer_gl.h"
+
+#include "base/memory/ptr_util.h"
+#include "chrome/browser/android/vr_shell/vr_shell_gpu_renderer.h"
+#include "content/public/browser/android/compositor.h"
+#include "gpu/command_buffer/client/gles2_interface.h"
+#include "gpu/command_buffer/common/mailbox.h"
+#include "gpu/command_buffer/common/sync_token.h"
+#include "gpu/ipc/client/gpu_channel_host.h"
+#include "gpu/ipc/common/gpu_surface_tracker.h"
+#include "services/ui/public/cpp/gpu/context_provider_command_buffer.h"
+#include "ui/gl/android/surface_texture.h"
+
+#include <android/native_window_jni.h>
+
+namespace vr_shell {
+
+VrShellCommandBufferGl::VrShellCommandBufferGl() : weak_ptr_factory_(this) {}
+
+VrShellCommandBufferGl::~VrShellCommandBufferGl() {}
+
+void VrShellCommandBufferGl::OnGpuChannelEstablished(
+    scoped_refptr<gpu::GpuChannelHost> gpu_channel_host) {
+  // Estimate the size of a large 16:9 surface used for offscreen rendering.
+  const size_t full_screen_texture_size_in_bytes = 4800 * 2700 * 4;
+
+  // TODO(klausw): investigate appropriate settings here. This is poorly
+  // documented.
+  gpu::SharedMemoryLimits limits;

[bajones, 2017/03/07 00:48:07]

Looks like this could probably use gpu::SharedMemoryLimits::ForMailboxContext()
instead of the magic numbers here?

[klausw, 2017/03/07 02:55:55]

Done.

+  limits.command_buffer_size = 64 * 1024;
+  limits.start_transfer_buffer_size = 64 * 1024;
+  limits.min_transfer_buffer_size = 64 * 1024;
+  limits.max_transfer_buffer_size = full_screen_texture_size_in_bytes;
+  limits.mapped_memory_reclaim_limit = full_screen_texture_size_in_bytes;
+
+  // Our attributes must be compatible with the shared offscreen
+  // surface used by virtualized contexts, otherwise mailbox
+  // synchronization doesn't work properly - it assumes a shared
+  // underlying GL context. TODO(klausw): is there a more official
+  // way to get default-compatible settings?
+  gpu::gles2::ContextCreationAttribHelper attributes;
+  attributes.alpha_size = -1;
+  attributes.red_size = 8;
+  attributes.green_size = 8;
+  attributes.blue_size = 8;
+  attributes.stencil_size = 0;
+  attributes.depth_size = 0;
+  attributes.samples = 0;
+  attributes.sample_buffers = 0;
+  attributes.bind_generates_resource = false;
+
+  bool automatic_flushes = false;
+  bool support_locking = false;
+  constexpr ui::ContextProviderCommandBuffer* shared_context_provider = nullptr;
+  context_provider_command_buffer_ =
+      make_scoped_refptr(new ui::ContextProviderCommandBuffer(
+          std::move(gpu_channel_host), gpu::GPU_STREAM_DEFAULT,
+          gpu::GpuStreamPriority::NORMAL, surface_handle_,
+          GURL("chrome://gpu/MusContextFactory"), automatic_flushes,

[bajones, 2017/03/07 00:48:07]

I believe we want to use a different URL here? Maybe
"chrome://gpu/VRContextFactory"?

[klausw, 2017/03/07 02:55:55]

Done, using chrome://gpu/WebVRContextFactory

+          support_locking, limits, attributes, shared_context_provider,
+          ui::command_buffer_metrics::MUS_CLIENT_CONTEXT));

[bajones, 2017/03/07 00:48:07]

I doubt Mus wants our command buffer metrics mixed in with theirs. Ideally this
should be a custom command_buffer_metrics, but for now it's probably better to
use CONTEXT_TYPE_UNKNOWN than MUS_CLIENT_CONTEXT.

[klausw, 2017/03/07 02:55:55]

Done.

+
+  if (!context_provider_command_buffer_->BindToCurrentThread()) {
+    LOG(ERROR) << __FUNCTION__ << ";;; failed to init ContextProvider";
+    return;
+  }
+
+  gl_ = context_provider_command_buffer_->ContextGL();
+
+  copy_renderer_ = base::MakeUnique<GpuRenderer>(gl_);
+}
+
+std::unique_ptr<gl::ScopedJavaSurface> VrShellCommandBufferGl::CreateSurface(
+    scoped_refptr<gl::SurfaceTexture> surface_texture) {
+  ANativeWindow* window = surface_texture->CreateSurface();
+  gpu::GpuSurfaceTracker* tracker = gpu::GpuSurfaceTracker::Get();
+  ANativeWindow_acquire(window);
+  // Skip ANativeWindow_setBuffersGeometry, the default size appears to work.
+  surface_handle_ = tracker->AddSurfaceForNativeWidget(window);
+
+  auto surface = base::MakeUnique<gl::ScopedJavaSurface>(surface_texture.get());
+  tracker->RegisterViewSurface(surface_handle_, surface->j_surface().obj());
+  // TODO(klausw): When should this be released? Does registering it
+  // keep it alive?
+  ANativeWindow_release(window);
+
+  gpu::GpuChannelEstablishFactory* factory =
+      content::Compositor::GetGpuChannelFactory();
+
+  factory->EstablishGpuChannel(
+      base::Bind(&VrShellCommandBufferGl::OnGpuChannelEstablished,
+                 weak_ptr_factory_.GetWeakPtr()));
+
+  return surface;
+}
+
+void VrShellCommandBufferGl::ResizeSurface(int width, int height) {
+  if (!gl_) {
+    LOG(ERROR) << "Cannot resize, not initialized";
+    return;
+  }
+  gl_->ResizeCHROMIUM(width, height, 1.f, false);
+  gl_->Viewport(0, 0, width, height);
+}
+
+bool VrShellCommandBufferGl::CopyFrameToSurface(int frame_index,
+                                                const gpu::Mailbox& mailbox,
+                                                gpu::SyncToken& sync_token,
+                                                bool discard) {
+  TRACE_EVENT1("gpu", "VrShellCommandBufferGl::CopyFrameToSurface", "frame",
+               frame_index);
+  if (!gl_) {
+    // We may not have a context yet, i.e. due to surface initialization
+    // being incomplete. This is not an error, but we obviously can't draw
+    // yet.
+    return false;
+  }
+
+  {
+    TRACE_EVENT0("gpu", "VrShellCommandBufferGl::WaitSyncToken");
+    gl_->WaitSyncTokenCHROMIUM(sync_token.GetData());
+  }
+
+  GLuint vrSourceTexture =
+      gl_->CreateAndConsumeTextureCHROMIUM(GL_TEXTURE_2D, mailbox.name);
+
+  if (discard) {
+    // We've consumed the texture, but the caller requested that we
+    // don't draw it because the previous one hasn't been consumed
+    // yet. (Swapping twice on a Surfacewithout consuming one in
+    // between from the SurfaceTexture can lose frames.) This should
+    // be rare, it's a waste of resources and can cause jerky
+    // animation due to the lost frames.
+    return false;
+  } else {
+    copy_renderer_->DrawQuad(gl_, vrSourceTexture);
+    gl_->SwapBuffers();
+    return true;
+  }
+}
+
+}  // namespace vr_shell