Clean up legacy IPC code in OzoneDRM

OzoneDrmMojo is at 100% in M81 and M83 branch cut has passed, feature is by default on in M83. Legacy IPC code should be removed.

Bug: 620927,806092
Change-Id: I40346e50df69515163a7b6e1df92b3a50a101bc1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2142332Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Reviewed-by: Michael Spang <spang@chromium.org>
Reviewed-by: Sunny Sachanandani <sunnyps@chromium.org>
Reviewed-by: Robert Kroeger <rjkroege@chromium.org>
Commit-Queue: Kramer Ge <fangzhoug@chromium.org>
Cr-Commit-Position: refs/heads/master@{#760334}

components/viz/host/gpu_host_impl.cc

@@ -283,36 +283,17 @@ void GpuHostImpl::InitOzone() {
   // The Ozone/Wayland requires mojo communication to be established to be
   // functional with a separate gpu process. Thus, using the PlatformProperties,
   // check if there is such a requirement.
-  if (features::IsOzoneDrmMojo() ||
-      ui::OzonePlatform::GetInstance()->GetPlatformProperties().requires_mojo) {
-    // TODO(rjkroege): Remove the legacy IPC code paths when no longer
-    // necessary. https://crbug.com/806092
-    auto interface_binder = base::BindRepeating(&GpuHostImpl::BindInterface,
-                                                weak_ptr_factory_.GetWeakPtr());
-    auto terminate_callback = base::BindOnce(&GpuHostImpl::TerminateGpuProcess,
-                                             weak_ptr_factory_.GetWeakPtr());
-
-    ui::OzonePlatform::GetInstance()
-        ->GetGpuPlatformSupportHost()
-        ->OnGpuServiceLaunched(params_.restart_id,
-                               params_.main_thread_task_runner,
-                               host_thread_task_runner_, interface_binder,
-                               std::move(terminate_callback));
-  } else {
-    auto send_callback = base::BindRepeating(
-        [](base::WeakPtr<GpuHostImpl> host, IPC::Message* message) {
-          if (host)
-            host->delegate_->SendGpuProcessMessage(message);
-          else
-            delete message;
-        },
-        weak_ptr_factory_.GetWeakPtr());
-    ui::OzonePlatform::GetInstance()
-        ->GetGpuPlatformSupportHost()
-        ->OnGpuProcessLaunched(params_.restart_id,
-                               params_.main_thread_task_runner,
-                               host_thread_task_runner_, send_callback);
-  }
+  auto interface_binder = base::BindRepeating(&GpuHostImpl::BindInterface,
+                                              weak_ptr_factory_.GetWeakPtr());
+  auto terminate_callback = base::BindOnce(&GpuHostImpl::TerminateGpuProcess,
+                                           weak_ptr_factory_.GetWeakPtr());
+
+  ui::OzonePlatform::GetInstance()
+      ->GetGpuPlatformSupportHost()
+      ->OnGpuServiceLaunched(params_.restart_id,
+                             params_.main_thread_task_runner,
+                             host_thread_task_runner_, interface_binder,
+                             std::move(terminate_callback));
 }
 
 void GpuHostImpl::TerminateGpuProcess(const std::string& message) {

gpu/command_buffer/tests/gl_tests_main.cc

@@ -40,7 +40,6 @@ class GlTestsSuite : public base::TestSuite {
     // Make Ozone run in single-process mode.
     ui::OzonePlatform::InitParams params;
     params.single_process = true;
-    params.using_mojo = true;
 
     // This initialization must be done after TaskEnvironment has
     // initialized the UI thread.

gpu/ipc/service/gpu_init.cc

@@ -276,7 +276,6 @@ bool GpuInit::InitializeAndStartSandbox(base::CommandLine* command_line,
   // may also have started at this point.
   ui::OzonePlatform::InitParams params;
   params.single_process = false;
-  params.using_mojo = features::IsOzoneDrmMojo();
   ui::OzonePlatform::InitializeForGPU(params);
   const std::vector<gfx::BufferFormat> supported_buffer_formats_for_texturing =
       ui::OzonePlatform::GetInstance()
@@ -560,7 +559,6 @@ void GpuInit::InitializeInProcess(base::CommandLine* command_line,
 #if defined(USE_OZONE)
   ui::OzonePlatform::InitParams params;
   params.single_process = true;
-  params.using_mojo = features::IsOzoneDrmMojo();
   ui::OzonePlatform::InitializeForGPU(params);
   const std::vector<gfx::BufferFormat> supported_buffer_formats_for_texturing =
       ui::OzonePlatform::GetInstance()

gpu/vulkan/tests/vulkan_tests_main.cc

@@ -32,7 +32,6 @@ class VulkanTestSuite : public base::TestSuite {
     // Make Ozone run in single-process mode.
     ui::OzonePlatform::InitParams params;
     params.single_process = true;
-    params.using_mojo = true;
 
     // This initialization must be done after TaskEnvironment has
     // initialized the UI thread.

ui/aura/env.cc

@@ -218,7 +218,6 @@ void Env::Init() {
   // instead of checking flags here.
   params.single_process = command_line->HasSwitch("single-process") ||
                           command_line->HasSwitch("in-process-gpu");
-  params.using_mojo = features::IsOzoneDrmMojo();
 
   ui::OzonePlatform::InitializeForUI(params);
 #endif

ui/base/ui_base_features.cc

@@ -186,13 +186,6 @@ bool IsUseCommonSelectPopupEnabled() {
 const base::Feature kWebUIA11yEnhancements{"WebUIA11yEnhancements",
                                            base::FEATURE_DISABLED_BY_DEFAULT};
 
-const base::Feature kEnableOzoneDrmMojo = {"OzoneDrmMojo",
-                                           base::FEATURE_ENABLED_BY_DEFAULT};
-
-bool IsOzoneDrmMojo() {
-  return base::FeatureList::IsEnabled(kEnableOzoneDrmMojo);
-}
-
 #if defined(OS_CHROMEOS)
 const base::Feature kHandwritingGesture = {"HandwritingGesture",
                                            base::FEATURE_DISABLED_BY_DEFAULT};

ui/base/ui_base_features.h

@@ -83,14 +83,6 @@ COMPONENT_EXPORT(UI_BASE_FEATURES)
 extern const base::Feature kUseCommonSelectPopup;
 COMPONENT_EXPORT(UI_BASE_FEATURES) bool IsUseCommonSelectPopupEnabled();
 
-// Use mojo communication in the drm platform instead of paramtraits. Remove
-// this switch (and associated code) when the drm platform always uses mojo
-// communication.
-// TODO(rjkroege): Remove in http://crbug.com/806092.
-COMPONENT_EXPORT(UI_BASE_FEATURES)
-extern const base::Feature kEnableOzoneDrmMojo;
-COMPONENT_EXPORT(UI_BASE_FEATURES) bool IsOzoneDrmMojo();
-
 #if defined(OS_CHROMEOS)
 COMPONENT_EXPORT(UI_BASE_FEATURES)
 extern const base::Feature kHandwritingGesture;

ui/gl/test/gl_image_test_support.cc

@@ -37,7 +37,6 @@ void GLImageTestSupport::InitializeGL(
 #if defined(USE_OZONE)
   ui::OzonePlatform::InitParams params;
   params.single_process = true;
-  params.using_mojo = true;
   ui::OzonePlatform::InitializeForGPU(params);
 #endif
 

ui/gl/test/run_all_unittests.cc

@@ -47,7 +47,6 @@ class GlTestSuite : public base::TestSuite {
     // and GPU components.
     ui::OzonePlatform::InitParams params;
     params.single_process = true;
-    params.using_mojo = true;
 
     // This initialization must be done after TaskEnvironment has
     // initialized the UI thread.

ui/ozone/demo/ozone_demo.cc

@@ -21,7 +21,6 @@
 #include "ui/events/ozone/layout/keyboard_layout_engine_manager.h"
 #include "ui/ozone/demo/simple_renderer_factory.h"
 #include "ui/ozone/demo/window_manager.h"
-#include "ui/ozone/public/ozone_gpu_test_helper.h"
 #include "ui/ozone/public/ozone_platform.h"
 
 const char kHelp[] = "help";
@@ -82,17 +81,6 @@ int main(int argc, char** argv) {
 
   ui::OzonePlatform::InitializeForGPU(params);
 
-  std::unique_ptr<ui::OzoneGpuTestHelper> gpu_helper;
-  if (!ui::OzonePlatform::GetInstance()
-           ->GetPlatformProperties()
-           .requires_mojo) {
-    // OzoneGpuTestHelper transports Chrome IPC messages between host & gpu code
-    // in single process mode. We don't use both Chrome IPC and mojo, so only
-    // initialize it for non-mojo platforms.
-    gpu_helper = std::make_unique<ui::OzoneGpuTestHelper>();
-    gpu_helper->Initialize(base::ThreadTaskRunnerHandle::Get());
-  }
-
   base::RunLoop run_loop;
 
   ui::WindowManager window_manager(

ui/ozone/demo/skia/skia_demo.cc

@@ -20,7 +20,6 @@
 #include "ui/events/ozone/layout/keyboard_layout_engine_manager.h"
 #include "ui/ozone/demo/skia/skia_renderer_factory.h"
 #include "ui/ozone/demo/window_manager.h"
-#include "ui/ozone/public/ozone_gpu_test_helper.h"
 #include "ui/ozone/public/ozone_platform.h"
 
 int main(int argc, char** argv) {
@@ -57,17 +56,6 @@ int main(int argc, char** argv) {
 
   ui::OzonePlatform::InitializeForGPU(params);
 
-  std::unique_ptr<ui::OzoneGpuTestHelper> gpu_helper;
-  if (!ui::OzonePlatform::GetInstance()
-           ->GetPlatformProperties()
-           .requires_mojo) {
-    // OzoneGpuTestHelper transports Chrome IPC messages between host & gpu code
-    // in single process mode. We don't use both Chrome IPC and mojo, so only
-    // initialize it for non-mojo platforms.
-    gpu_helper = std::make_unique<ui::OzoneGpuTestHelper>();
-    gpu_helper->Initialize(base::ThreadTaskRunnerHandle::Get());
-  }
-
   base::RunLoop run_loop;
 
   ui::WindowManager window_manager(std::make_unique<ui::SkiaRendererFactory>(),

ui/ozone/platform/drm/BUILD.gn

@@ -54,8 +54,6 @@ source_set("gbm") {
     "gpu/drm_overlay_validator.h",
     "gpu/drm_thread.cc",
     "gpu/drm_thread.h",
-    "gpu/drm_thread_message_proxy.cc",
-    "gpu/drm_thread_message_proxy.h",
     "gpu/drm_thread_proxy.cc",
     "gpu/drm_thread_proxy.h",
     "gpu/drm_window.cc",
@@ -102,8 +100,6 @@ source_set("gbm") {
     "host/drm_display_host.h",
     "host/drm_display_host_manager.cc",
     "host/drm_display_host_manager.h",
-    "host/drm_gpu_platform_support_host.cc",
-    "host/drm_gpu_platform_support_host.h",
     "host/drm_native_display_delegate.cc",
     "host/drm_native_display_delegate.h",
     "host/drm_window_host.cc",

ui/ozone/platform/drm/gpu/drm_thread_message_proxy.h

-// Copyright 2015 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.
-
-#ifndef UI_OZONE_PLATFORM_DRM_GPU_DRM_THREAD_MESSAGE_PROXY_H_
-#define UI_OZONE_PLATFORM_DRM_GPU_DRM_THREAD_MESSAGE_PROXY_H_
-
-#include <stdint.h>
-
-#include "base/macros.h"
-#include "base/memory/weak_ptr.h"
-#include "ipc/message_filter.h"
-#include "ui/display/types/display_constants.h"
-#include "ui/display/types/gamma_ramp_rgb_entry.h"
-#include "ui/gfx/native_widget_types.h"
-#include "ui/ozone/platform/drm/common/display_types.h"
-#include "ui/ozone/platform/drm/gpu/inter_thread_messaging_proxy.h"
-
-namespace base {
-struct FileDescriptor;
-class FilePath;
-}
-
-namespace gfx {
-class Point;
-class Rect;
-}
-
-namespace ui {
-class DrmThread;
-struct DisplayMode_Params;
-
-class DrmThreadMessageProxy : public IPC::MessageFilter,
-                              public InterThreadMessagingProxy {
- public:
-  DrmThreadMessageProxy();
-
-  // InterThreadMessagingProxy.
-  void SetDrmThread(DrmThread* thread) override;
-
-  // IPC::MessageFilter:
-  void OnFilterAdded(IPC::Channel* channel) override;
-  bool OnMessageReceived(const IPC::Message& message) override;
-
- private:
-  ~DrmThreadMessageProxy() override;
-
-  void OnCreateWindow(gfx::AcceleratedWidget widget,
-                      const gfx::Rect& initial_bounds);
-  void OnDestroyWindow(gfx::AcceleratedWidget widget);
-  void OnWindowBoundsChanged(gfx::AcceleratedWidget widget,
-                             const gfx::Rect& bounds);
-  void OnCursorSet(gfx::AcceleratedWidget widget,
-                   const std::vector<SkBitmap>& bitmaps,
-                   const gfx::Point& location,
-                   int frame_delay_ms);
-  void OnCursorMove(gfx::AcceleratedWidget widget, const gfx::Point& location);
-
-  // Display related IPC handlers.
-  void OnRefreshNativeDisplays();
-  void OnConfigureNativeDisplay(int64_t id,
-                                const DisplayMode_Params& mode,
-                                const gfx::Point& origin);
-  void OnDisableNativeDisplay(int64_t id);
-  void OnTakeDisplayControl();
-  void OnRelinquishDisplayControl();
-  void OnAddGraphicsDevice(const base::FilePath& path,
-                           const base::FileDescriptor& fd);
-  void OnRemoveGraphicsDevice(const base::FilePath& path);
-  void OnGetHDCPState(int64_t display_id);
-  void OnSetHDCPState(int64_t display_id, display::HDCPState state);
-  void OnSetColorMatrix(int64_t display_id,
-                        const std::vector<float>& color_matrix);
-  void OnSetGammaCorrection(
-      int64_t display_id,
-      const std::vector<display::GammaRampRGBEntry>& degamma_lut,
-      const std::vector<display::GammaRampRGBEntry>& gamma_lut);
-  void OnSetPrivacyScreen(int64_t display_id, bool enabled);
-  void OnRefreshNativeDisplaysCallback(MovableDisplaySnapshots displays) const;
-  void OnConfigureNativeDisplayCallback(int64_t display_id, bool success) const;
-  void OnDisableNativeDisplayCallback(int64_t display_id, bool success) const;
-  void OnTakeDisplayControlCallback(bool success) const;
-  void OnRelinquishDisplayControlCallback(bool success) const;
-  void OnGetHDCPStateCallback(int64_t display_id,
-                              bool success,
-                              display::HDCPState state) const;
-  void OnSetHDCPStateCallback(int64_t display_id, bool success) const;
-
-  DrmThread* drm_thread_ = nullptr;
-
-  IPC::Sender* sender_ = nullptr;
-
-  base::WeakPtrFactory<DrmThreadMessageProxy> weak_ptr_factory_{this};
-
-  DISALLOW_COPY_AND_ASSIGN(DrmThreadMessageProxy);
-};
-
-}  // namespace ui
-
-#endif  // UI_OZONE_PLATFORM_DRM_GPU_DRM_THREAD_MESSAGE_PROXY_H_

ui/ozone/platform/drm/gpu/drm_thread_proxy.cc

@@ -8,10 +8,10 @@
 #include <utility>
 
 #include "base/bind.h"
+#include "base/trace_event/trace_event.h"
 #include "ui/gfx/linux/gbm_wrapper.h"
 #include "ui/ozone/platform/drm/gpu/drm_device.h"
 #include "ui/ozone/platform/drm/gpu/drm_device_generator.h"
-#include "ui/ozone/platform/drm/gpu/drm_thread_message_proxy.h"
 #include "ui/ozone/platform/drm/gpu/drm_window_proxy.h"
 #include "ui/ozone/platform/drm/gpu/gbm_pixmap.h"
 #include "ui/ozone/platform/drm/gpu/proxy_helpers.h"
@@ -62,12 +62,6 @@ DrmThreadProxy::DrmThreadProxy() = default;
 
 DrmThreadProxy::~DrmThreadProxy() = default;
 
-// Used only with the paramtraits implementation.
-void DrmThreadProxy::BindThreadIntoMessagingProxy(
-    InterThreadMessagingProxy* messaging_proxy) {
-  messaging_proxy->SetDrmThread(&drm_thread_);
-}
-
 void DrmThreadProxy::StartDrmThread(base::OnceClosure receiver_drainer) {
   drm_thread_.Start(std::move(receiver_drainer),
                     std::make_unique<GbmDeviceGenerator>());

ui/ozone/platform/drm/host/drm_gpu_platform_support_host.h

-// Copyright 2014 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.
-
-#ifndef UI_OZONE_PLATFORM_DRM_HOST_DRM_GPU_PLATFORM_SUPPORT_HOST_H_
-#define UI_OZONE_PLATFORM_DRM_HOST_DRM_GPU_PLATFORM_SUPPORT_HOST_H_
-
-#include <vector>
-
-#include "base/callback.h"
-#include "base/observer_list.h"
-#include "base/single_thread_task_runner.h"
-#include "ui/display/types/display_constants.h"
-#include "ui/gfx/native_widget_types.h"
-#include "ui/ozone/common/gpu/ozone_gpu_message_params.h"
-#include "ui/ozone/platform/drm/host/gpu_thread_adapter.h"
-#include "ui/ozone/public/gpu_platform_support_host.h"
-
-namespace gfx {
-class Point;
-}
-
-namespace ui {
-
-class DrmCursor;
-class DrmDisplayHostMananger;
-class GpuThreadObserver;
-
-class DrmGpuPlatformSupportHost : public GpuPlatformSupportHost,
-                                  public GpuThreadAdapter,
-                                  public IPC::Sender {
- public:
-  explicit DrmGpuPlatformSupportHost(DrmCursor* cursor);
-  ~DrmGpuPlatformSupportHost() override;
-
-  // GpuPlatformSupportHost:
-  void OnGpuProcessLaunched(
-      int host_id,
-      scoped_refptr<base::SingleThreadTaskRunner> ui_runner,
-      scoped_refptr<base::SingleThreadTaskRunner> send_runner,
-      base::RepeatingCallback<void(IPC::Message*)> send_callback) override;
-  void OnChannelDestroyed(int host_id) override;
-  void OnGpuServiceLaunched(
-      int host_id,
-      scoped_refptr<base::SingleThreadTaskRunner> ui_runner,
-      scoped_refptr<base::SingleThreadTaskRunner> io_runner,
-      GpuHostBindInterfaceCallback binder,
-      GpuHostTerminateCallback terminate_callback) override;
-
-  void OnMessageReceived(const IPC::Message& message) override;
-
-  // IPC::Sender:
-  bool Send(IPC::Message* message) override;
-
-  // GpuThreadAdapter.
-  // Core functionality.
-  void AddGpuThreadObserver(GpuThreadObserver* observer) override;
-  void RemoveGpuThreadObserver(GpuThreadObserver* observer) override;
-  bool IsConnected() override;
-
-  // Services needed for DrmDisplayHostMananger.
-  void RegisterHandlerForDrmDisplayHostManager(
-      DrmDisplayHostManager* handler) override;
-  void UnRegisterHandlerForDrmDisplayHostManager() override;
-
-  bool GpuTakeDisplayControl() override;
-  bool GpuRefreshNativeDisplays() override;
-  bool GpuRelinquishDisplayControl() override;
-  bool GpuAddGraphicsDeviceOnUIThread(const base::FilePath& path,
-                                      base::ScopedFD fd) override;
-  void GpuAddGraphicsDeviceOnIOThread(const base::FilePath& path,
-                                      base::ScopedFD fd) override;
-  bool GpuRemoveGraphicsDevice(const base::FilePath& path) override;
-
-  // Services needed by DrmDisplayHost
-  bool GpuConfigureNativeDisplay(int64_t display_id,
-                                 const ui::DisplayMode_Params& display_mode,
-                                 const gfx::Point& point) override;
-  bool GpuDisableNativeDisplay(int64_t display_id) override;
-  bool GpuGetHDCPState(int64_t display_id) override;
-  bool GpuSetHDCPState(int64_t display_id, display::HDCPState state) override;
-  bool GpuSetColorMatrix(int64_t display_id,
-                         const std::vector<float>& color_matrix) override;
-  bool GpuSetGammaCorrection(
-      int64_t display_id,
-      const std::vector<display::GammaRampRGBEntry>& degamma_lut,
-      const std::vector<display::GammaRampRGBEntry>& gamma_lut) override;
-  bool GpuSetPrivacyScreen(int64_t display_id, bool enabled) override;
-
-  // Services needed by DrmWindowHost
-  bool GpuDestroyWindow(gfx::AcceleratedWidget widget) override;
-  bool GpuCreateWindow(gfx::AcceleratedWidget widget,
-                       const gfx::Rect& initial_bounds) override;
-  bool GpuWindowBoundsChanged(gfx::AcceleratedWidget widget,
-                              const gfx::Rect& bounds) override;
-
- private:
-  void OnChannelEstablished();
-  void OnUpdateNativeDisplays(
-      const std::vector<DisplaySnapshot_Params>& displays);
-  void OnDisplayConfigured(int64_t display_id, bool status);
-  void OnHDCPStateReceived(int64_t display_id,
-                           bool status,
-                           display::HDCPState state);
-  void OnHDCPStateUpdated(int64_t display_id, bool status);
-  void OnTakeDisplayControl(bool status);
-  void OnRelinquishDisplayControl(bool status);
-
-  int host_id_ = -1;
-  bool channel_established_ = false;
-
-  scoped_refptr<base::SingleThreadTaskRunner> ui_runner_;
-  scoped_refptr<base::SingleThreadTaskRunner> send_runner_;
-  base::RepeatingCallback<void(IPC::Message*)> send_callback_;
-
-  DrmDisplayHostManager* display_manager_;  // Not owned.
-
-  DrmCursor* const cursor_;  // Not owned.
-  base::ObserverList<GpuThreadObserver>::Unchecked gpu_thread_observers_;
-
-  base::WeakPtr<DrmGpuPlatformSupportHost> weak_ptr_;
-  base::WeakPtrFactory<DrmGpuPlatformSupportHost> weak_ptr_factory_{this};
-  DISALLOW_COPY_AND_ASSIGN(DrmGpuPlatformSupportHost);
-};
-
-}  // namespace ui
-
-#endif  // UI_OZONE_PLATFORM_DRM_HOST_DRM_GPU_PLATFORM_SUPPORT_HOST_H_

ui/ozone/platform/drm/host/host_drm_device.h

@@ -97,9 +97,6 @@ class HostDrmDevice : public base::RefCountedThreadSafe<HostDrmDevice>,
 
   void OnDrmServiceStarted();
 
-  // TODO(rjkroege): Get rid of the need for this method in a subsequent CL.
-  void PollForSingleThreadReady(int previous_delay);
-
   void GpuConfigureNativeDisplayCallback(int64_t display_id,
                                          bool success) const;
 

ui/ozone/platform/drm/ozone_platform_gbm.cc

@@ -32,14 +32,12 @@
 #include "ui/ozone/platform/drm/gpu/drm_framebuffer.h"
 #include "ui/ozone/platform/drm/gpu/drm_gpu_display_manager.h"
 #include "ui/ozone/platform/drm/gpu/drm_overlay_manager_gpu.h"
-#include "ui/ozone/platform/drm/gpu/drm_thread_message_proxy.h"
 #include "ui/ozone/platform/drm/gpu/drm_thread_proxy.h"
 #include "ui/ozone/platform/drm/gpu/gbm_surface_factory.h"
 #include "ui/ozone/platform/drm/gpu/proxy_helpers.h"
 #include "ui/ozone/platform/drm/host/drm_cursor.h"
 #include "ui/ozone/platform/drm/host/drm_device_connector.h"
 #include "ui/ozone/platform/drm/host/drm_display_host_manager.h"
-#include "ui/ozone/platform/drm/host/drm_gpu_platform_support_host.h"
 #include "ui/ozone/platform/drm/host/drm_native_display_delegate.h"
 #include "ui/ozone/platform/drm/host/drm_window_host.h"
 #include "ui/ozone/platform/drm/host/drm_window_host_manager.h"
@@ -87,13 +85,6 @@ class OzonePlatformGbm : public OzonePlatform {
   InputController* GetInputController() override {
     return event_factory_ozone_->input_controller();
   }
-  IPC::MessageFilter* GetGpuMessageFilter() override {
-    if (using_mojo_) {
-      return nullptr;
-    } else {
-      return gpu_message_filter_.get();
-    }
-  }
 
   std::unique_ptr<PlatformScreen> CreateScreen() override {
     NOTREACHED();
@@ -101,11 +92,7 @@ class OzonePlatformGbm : public OzonePlatform {
   }
 
   GpuPlatformSupportHost* GetGpuPlatformSupportHost() override {
-    if (using_mojo_) {
       return drm_device_connector_.get();
-    } else {
-      return gpu_platform_support_host_.get();
-    }
   }
 
   std::unique_ptr<SystemInputInjector> CreateSystemInputInjector() override {
@@ -115,14 +102,10 @@ class OzonePlatformGbm : public OzonePlatform {
   // In multi-process mode, this function must be executed in Viz as it sets up
   // the callbacks needed for Mojo receivers. In single process mode, it may be
   // called on any thread. It must follow one of |InitializeUI| or
-  // |InitializeGPU|. Invocations of this method when not using mojo will be
-  // ignored. While the caller may choose to invoke this method before entering
-  // the sandbox, the actual interface adding has to happen on the DRM Device
-  // thread and so will be deferred until the DRM thread is running.
+  // |InitializeGPU|. While the caller may choose to invoke this method before
+  // entering the sandbox, the actual interface adding has to happen on the DRM
+  // Device thread and so will be deferred until the DRM thread is running.
   void AddInterfaces(mojo::BinderMap* binders) override {
-    if (!using_mojo_)
-      return;
-
     binders->Add<ozone::mojom::DrmDevice>(
         base::BindRepeating(&OzonePlatformGbm::CreateDrmDeviceReceiver,
                             weak_factory_.GetWeakPtr()),
@@ -153,10 +136,7 @@ class OzonePlatformGbm : public OzonePlatform {
   std::unique_ptr<PlatformWindow> CreatePlatformWindow(
       PlatformWindowDelegate* delegate,
       PlatformWindowInitProperties properties) override {
-    GpuThreadAdapter* adapter = gpu_platform_support_host_.get();
-    if (using_mojo_) {
-      adapter = host_drm_device_.get();
-    }
+    GpuThreadAdapter* adapter = host_drm_device_.get();
 
     auto platform_window = std::make_unique<DrmWindowHost>(
         delegate, properties.bounds, adapter, event_factory_ozone_.get(),
@@ -185,16 +165,13 @@ class OzonePlatformGbm : public OzonePlatform {
   }
 
   void InitializeUI(const InitParams& args) override {
-    // Ozone drm can operate in three modes configured at runtime.
-    //   1. legacy mode where host and viz components communicate
-    //      via param traits IPC. This will be soon deprecated in favor of 3.
-    //   2. single-process mode where host and viz components
+    // Ozone drm can operate in two modes configured at runtime.
+    //   1. single-process mode where host and viz components
     //      communicate via in-process mojo. Single-process mode can be single
     //      or multi-threaded.
-    //   3. multi-process mode where host and viz components communicate
+    //   2. multi-process mode where host and viz components communicate
     //      via mojo IPC.
 
-    using_mojo_ = args.using_mojo;
     host_thread_ = base::PlatformThread::CurrentRef();
 
     device_manager_ = CreateDeviceManager();
@@ -216,47 +193,28 @@ class OzonePlatformGbm : public OzonePlatform {
 
     GpuThreadAdapter* adapter;
 
-    if (using_mojo_) {
-      host_drm_device_ = base::MakeRefCounted<HostDrmDevice>(cursor_.get());
-      drm_device_connector_ =
-          std::make_unique<DrmDeviceConnector>(host_drm_device_);
-      adapter = host_drm_device_.get();
-    } else {
-      gpu_platform_support_host_ =
-          std::make_unique<DrmGpuPlatformSupportHost>(cursor_.get());
-      adapter = gpu_platform_support_host_.get();
-    }
+    host_drm_device_ = base::MakeRefCounted<HostDrmDevice>(cursor_.get());
+    drm_device_connector_ =
+        std::make_unique<DrmDeviceConnector>(host_drm_device_);
+    adapter = host_drm_device_.get();
 
     display_manager_ = std::make_unique<DrmDisplayHostManager>(
         adapter, device_manager_.get(), &host_properties_,
         event_factory_ozone_->input_controller());
     cursor_factory_ozone_ = std::make_unique<BitmapCursorFactoryOzone>();
 
-    if (using_mojo_)
-      host_drm_device_->SetDisplayManager(display_manager_.get());
+    host_drm_device_->SetDisplayManager(display_manager_.get());
   }
 
   void InitializeGPU(const InitParams& args) override {
-    using_mojo_ = args.using_mojo;
     gpu_task_runner_ = base::ThreadTaskRunnerHandle::Get();
 
-    InterThreadMessagingProxy* itmp;
-    if (!using_mojo_) {
-      scoped_refptr<DrmThreadMessageProxy> message_proxy(
-          new DrmThreadMessageProxy());
-      itmp = message_proxy.get();
-      gpu_message_filter_ = std::move(message_proxy);
-    }
-
     // NOTE: Can't start the thread here since this is called before sandbox
     // initialization in multi-process Chrome.
     drm_thread_proxy_ = std::make_unique<DrmThreadProxy>();
 
     surface_factory_ =
         std::make_unique<GbmSurfaceFactory>(drm_thread_proxy_.get());
-    if (!using_mojo_) {
-      drm_thread_proxy_->BindThreadIntoMessagingProxy(itmp);
-    }
 
     overlay_manager_ =
         std::make_unique<DrmOverlayManagerGpu>(drm_thread_proxy_.get());
@@ -266,12 +224,14 @@ class OzonePlatformGbm : public OzonePlatform {
     if (!single_process())
       return;
 
-    // In single process/mojo mode we need to make sure DrainReceiverRequest is
-    // executed on this thread before we start the drm device.
-    const bool block_for_drm_thread = using_mojo_;
+    // Note we exit this code above when running in multiple processes and so
+    // following code only executes in single process mode. In single process
+    // mode we need to make sure DrainReceiverRequest is executed on this thread
+    // before we start the drm device.
+    const bool block_for_drm_thread = true;
     StartDrmThread(block_for_drm_thread);
 
-    if (using_mojo_ && host_thread_ == base::PlatformThread::CurrentRef()) {
+    if (host_thread_ == base::PlatformThread::CurrentRef()) {
       CHECK(has_initialized_ui()) << "Mojo single-thread mode requires "
                                      "InitializeUI to be called first.";
       // Connect host and gpu here since OnGpuServiceLaunched() is not called in
@@ -319,12 +279,9 @@ class OzonePlatformGbm : public OzonePlatform {
     }
   }
 
-  bool using_mojo_ = false;
-
   // Objects in the GPU process.
   std::unique_ptr<DrmThreadProxy> drm_thread_proxy_;
   std::unique_ptr<GbmSurfaceFactory> surface_factory_;
-  scoped_refptr<IPC::MessageFilter> gpu_message_filter_;
   scoped_refptr<base::SingleThreadTaskRunner> gpu_task_runner_;
   std::unique_ptr<DrmOverlayManager> overlay_manager_;
 
@@ -334,16 +291,11 @@ class OzonePlatformGbm : public OzonePlatform {
       pending_gpu_adapter_receivers_;
   bool drm_thread_started_ = false;
 
-  // gpu_platform_support_host_ is the IPC bridge to the GPU process while
   // host_drm_device_ is the mojo bridge to the Viz process. Only one can be in
   // use at any time.
-  // TODO(rjkroege): Remove gpu_platform_support_host_ once ozone/drm with mojo
-  // has reached the stable channel.
-  // A raw pointer to either |gpu_platform_support_host_| or |host_drm_device_|
-  // is passed to |display_manager_| in InitializeUI(). To avoid a use after
-  // free, the following two members should be declared before the two managers,
-  // so that they're deleted after them.
-  std::unique_ptr<DrmGpuPlatformSupportHost> gpu_platform_support_host_;
+  // A raw pointer to |host_drm_device_| is passed to |display_manager_| in
+  // InitializeUI(). To avoid a use after free, the following two members should
+  // be declared before the two managers, so that they're deleted after them.
 
   // Objects in the host process.
 #if BUILDFLAG(USE_XKBCOMMON)

ui/ozone/platform/scenic/ozone_platform_scenic.cc

@@ -46,7 +46,6 @@ constexpr OzonePlatform::PlatformProperties kScenicPlatformProperties{
     /*needs_view_token=*/true,
     /*custom_frame_pref_default=*/false,
     /*use_system_title_bar=*/false,
-    /*requires_mojo=*/true,
     /*message_pump_type_for_gpu=*/base::MessagePumpType::IO};
 
 class ScenicPlatformEventSource : public ui::PlatformEventSource {

ui/ozone/platform/wayland/ozone_platform_wayland.cc

@@ -71,12 +71,6 @@ constexpr OzonePlatform::PlatformProperties kWaylandPlatformProperties = {
     // https://github.com/wayland-project/wayland-protocols/commit/76d1ae8c65739eff3434ef219c58a913ad34e988
     /*custom_frame_pref_default=*/true,
     /*use_system_title_bar=*/false,
-
-    // Ozone/Wayland relies on the mojo communication when running in
-    // !single_process.
-    // TODO(msisov, rjkroege): Remove after http://crbug.com/806092.
-    /*requires_mojo=*/true,
-
     /*message_pump_type_for_gpu=*/base::MessagePumpType::DEFAULT};
 
 class OzonePlatformWayland : public OzonePlatform {

ui/ozone/platform/x11/ozone_platform_x11.cc

@@ -60,7 +60,6 @@ constexpr OzonePlatform::PlatformProperties kX11PlatformProperties{
     /*needs_view_token=*/false,
     /*custom_frame_pref_default=*/false,
     /*use_system_title_bar=*/true,
-    /*requires_mojo=*/false,
 
     // When the Ozone X11 backend is running, use a UI loop to grab Expose
     // events. See GLSurfaceGLX and https://crbug.com/326995.

ui/ozone/public/ozone_platform.h

@@ -71,14 +71,6 @@ class COMPONENT_EXPORT(OZONE) OzonePlatform {
     // operate as a single process for platforms (i.e. drm) that are usually
     // split between a host and viz specific portion.
     bool single_process = false;
-
-    // Setting this to true indicates that the platform implementation should
-    // use mojo. Setting this to true requires calling |AddInterfaces|
-    // afterwards in the Viz process. Note that this param is only checked in
-    // Ozone DRM. Other platforms either never use mojo or always use mojo
-    // regardless of this param.
-    // TODO(crbug.com/806092): Remove after legacy IPC-based Ozone is removed.
-    bool using_mojo = false;
   };
 
   // Struct used to indicate platform properties.
@@ -95,10 +87,6 @@ class COMPONENT_EXPORT(OZONE) OzonePlatform {
     // supported.
     bool use_system_title_bar = false;
 
-    // Determines if the platform requires mojo communication for the IPC.
-    // Currently used only by the Ozone/Wayland platform.
-    bool requires_mojo = false;
-
     // Determines the type of message pump that should be used for GPU main
     // thread.
     base::MessagePumpType message_pump_type_for_gpu =