Revert of Create GPU child window on new thread.

gpu/ipc/service/child_window_surface_win.cc

Index: gpu/ipc/service/child_window_surface_win.cc
diff --git a/gpu/ipc/service/child_window_surface_win.cc b/gpu/ipc/service/child_window_surface_win.cc
index 362e182b9f82e6b05c7c4beb893d5bf0d3fa7717..762fbd117391233704e07375d64474912e305e1c 100644
--- a/gpu/ipc/service/child_window_surface_win.cc
+++ b/gpu/ipc/service/child_window_surface_win.cc
@@ -7,8 +7,6 @@
 #include <memory>
 
 #include "base/compiler_specific.h"
-#include "base/memory/ptr_util.h"
-#include "base/threading/thread.h"
 #include "base/win/scoped_hdc.h"
 #include "base/win/wrapped_window_proc.h"
 #include "gpu/ipc/common/gpu_messages.h"
@@ -24,21 +22,10 @@
 
 namespace gpu {
 
-// This owns the thread and contains data that's shared between the threads.
-struct SharedData {
-  SharedData() : thread("Window owner thread") {}
-
-  base::Lock rect_lock;
-  gfx::Rect rect_to_clear;
-
-  base::Thread thread;
-};
-
 namespace {
 
 ATOM g_window_class;
 
-// This runs on the window owner thread.
 LRESULT CALLBACK IntermediateWindowProc(HWND window,
                                         UINT message,
                                         WPARAM w_param,
@@ -50,14 +37,15 @@
     case WM_PAINT:
       PAINTSTRUCT paint;
       if (BeginPaint(window, &paint)) {
-        SharedData* shared_data =
-            reinterpret_cast<SharedData*>(gfx::GetWindowUserData(window));
-        DCHECK(shared_data);
-        {
-          base::AutoLock lock(shared_data->rect_lock);
-          shared_data->rect_to_clear.Union(gfx::Rect(paint.rcPaint));
-        }
-
+        ChildWindowSurfaceWin* window_surface =
+            reinterpret_cast<ChildWindowSurfaceWin*>(
+                gfx::GetWindowUserData(window));
+        DCHECK(window_surface);
+
+        // Wait to clear the contents until a GL draw occurs, as otherwise an
+        // unsightly black flash may happen if the GL contents are still
+        // transparent.
+        window_surface->InvalidateWindowRect(gfx::Rect(paint.rcPaint));
         EndPaint(window, &paint);
       }
       return 0;
@@ -66,7 +54,6 @@
   }
 }
 
-// This runs on the window owner thread.
 void InitializeWindowClass() {
   if (g_window_class)
     return;
@@ -83,40 +70,7 @@
     return;
   }
 }
-
-// This runs on the window owner thread.
-void CreateChildWindow(HWND parent,
-                       base::WaitableEvent* event,
-                       SharedData* shared_data,
-                       HWND* result) {
-  InitializeWindowClass();
-  DCHECK(g_window_class);
-
-  RECT windowRect;
-  GetClientRect(parent, &windowRect);
-
-  HWND window = CreateWindowEx(
-      WS_EX_NOPARENTNOTIFY, reinterpret_cast<wchar_t*>(g_window_class), L"",
-      WS_CHILDWINDOW | WS_DISABLED | WS_VISIBLE, 0, 0,
-      windowRect.right - windowRect.left, windowRect.bottom - windowRect.top,
-      ui::GetHiddenWindow(), NULL, NULL, NULL);
-  *result = window;
-  gfx::SetWindowUserData(window, shared_data);
-  event->Signal();
-}
-
-// This runs on the main thread after the window was destroyed on window owner
-// thread.
-void DestroySharedData(std::unique_ptr<SharedData> shared_data) {
-  shared_data->thread.Stop();
-}
-
-// This runs on the window owner thread.
-void DestroyWindowOnThread(HWND window) {
-  DestroyWindow(window);
-}
-
-}  // namespace
+}
 
 ChildWindowSurfaceWin::ChildWindowSurfaceWin(GpuChannelManager* manager,
                                              HWND parent_window)
@@ -163,19 +117,18 @@
 bool ChildWindowSurfaceWin::InitializeNativeWindow() {
   if (window_)
     return true;
-
-  shared_data_ = base::MakeUnique<SharedData>();
-
-  base::Thread::Options options(base::MessageLoop::TYPE_UI, 0);
-  shared_data_->thread.StartWithOptions(options);
-
-  base::WaitableEvent event(base::WaitableEvent::ResetPolicy::AUTOMATIC,
-                            base::WaitableEvent::InitialState::NOT_SIGNALED);
-  shared_data_->thread.task_runner()->PostTask(
-      FROM_HERE, base::Bind(&CreateChildWindow, parent_window_, &event,
-                            shared_data_.get(), &window_));
-  event.Wait();
-
+  InitializeWindowClass();
+  DCHECK(g_window_class);
+
+  RECT windowRect;
+  GetClientRect(parent_window_, &windowRect);
+
+  window_ = CreateWindowEx(
+      WS_EX_NOPARENTNOTIFY, reinterpret_cast<wchar_t*>(g_window_class), L"",
+      WS_CHILDWINDOW | WS_DISABLED | WS_VISIBLE, 0, 0,
+      windowRect.right - windowRect.left, windowRect.bottom - windowRect.top,
+      ui::GetHiddenWindow(), NULL, NULL, NULL);
+  gfx::SetWindowUserData(window_, this);
   manager_->delegate()->SendAcceleratedSurfaceCreatedChildWindow(parent_window_,
                                                                  window_);
   return true;
@@ -252,28 +205,26 @@
   return result;
 }
 
+void ChildWindowSurfaceWin::InvalidateWindowRect(const gfx::Rect& rect) {
+  rect_to_clear_.Union(rect);
+}
+
 void ChildWindowSurfaceWin::ClearInvalidContents() {
-  base::AutoLock lock(shared_data_->rect_lock);
-  if (!shared_data_->rect_to_clear.IsEmpty()) {
+  if (!rect_to_clear_.IsEmpty()) {
     base::win::ScopedGetDC dc(window_);
 
-    RECT rect = shared_data_->rect_to_clear.ToRECT();
+    RECT rect = rect_to_clear_.ToRECT();
 
     // DirectComposition composites with the contents under the SwapChain,
     // so ensure that's cleared. GDI treats black as transparent.
     FillRect(dc, &rect, reinterpret_cast<HBRUSH>(GetStockObject(BLACK_BRUSH)));
-    shared_data_->rect_to_clear = gfx::Rect();
+    rect_to_clear_ = gfx::Rect();
   }
 }
 
 ChildWindowSurfaceWin::~ChildWindowSurfaceWin() {
-  if (shared_data_) {
-    scoped_refptr<base::TaskRunner> task_runner =
-        shared_data_->thread.task_runner();
-    task_runner->PostTaskAndReply(
-        FROM_HERE, base::Bind(&DestroyWindowOnThread, window_),
-        base::Bind(&DestroySharedData, base::Passed(std::move(shared_data_))));
-  }
+  gfx::SetWindowUserData(window_, nullptr);
+  DestroyWindow(window_);
 }
 
 }  // namespace gpu