Add window styles to avoid events hit test to wrong window.

Based on Windows folks reply, this scroll lagging issue is because the
message hit test to wrong window (Intermediate D3D Window) and need to
forward to the correct window (Chrome Legacy Window), but Chrome Legacy
Window is holding the input queue lock so Intermediate D3D Window can
not forward the message.

This fix adding 3 window extended styles to Intermediate D3D Window:

WS_EX_LAYERED | WS_EX_TRANSPARENT | WS_EX_NOREDIRECTIONBITMAP

The first two should make the window transparent for input, and the
third avoids allocating a bitmap that would otherwise be allocated with
WS_EX_LAYERED.

WM_PAINT, WM_ERASEBKGD and ClearInvalidContents() also removed because
they unnecessary for transparent layered window.

Bug: 871257
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Change-Id: Ic708b4d2a5a37f8e2e98e425c1be8b28de41d001
Reviewed-on: https://chromium-review.googlesource.com/c/1299342
Commit-Queue: Jianpeng Chao <chaopeng@chromium.org>
Reviewed-by: Sunny Sachanandani <sunnyps@chromium.org>
Reviewed-by: Bruce Dawson <brucedawson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#603073}

gpu/ipc/service/child_window_win.cc

@@ -9,7 +9,6 @@
 #include "base/compiler_specific.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop/message_loop.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"
@@ -21,48 +20,10 @@
 
 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,
-                                        LPARAM l_param) {
-  switch (message) {
-    case WM_ERASEBKGND:
-      // Prevent windows from erasing the background.
-      return 1;
-    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));
-        }
-
-        EndPaint(window, &paint);
-      }
-      return 0;
-    default:
-      return DefWindowProc(window, message, w_param, l_param);
-  }
-}
-
 // This runs on the window owner thread.
 void InitializeWindowClass() {
   if (g_window_class)
@@ -71,9 +32,9 @@ void InitializeWindowClass() {
   WNDCLASSEX intermediate_class;
   base::win::InitializeWindowClass(
       L"Intermediate D3D Window",
-      &base::win::WrappedWindowProc<IntermediateWindowProc>, CS_OWNDC, 0, 0,
-      nullptr, reinterpret_cast<HBRUSH>(GetStockObject(BLACK_BRUSH)), nullptr,
-      nullptr, nullptr, &intermediate_class);
+      &base::win::WrappedWindowProc<::DefWindowProc>, CS_OWNDC, 0, 0, nullptr,
+      reinterpret_cast<HBRUSH>(GetStockObject(BLACK_BRUSH)), nullptr, nullptr,
+      nullptr, &intermediate_class);
   g_window_class = RegisterClassEx(&intermediate_class);
   if (!g_window_class) {
     LOG(ERROR) << "RegisterClass failed.";
@@ -122,7 +83,6 @@ class HiddenPopupWindow : public gfx::WindowImpl {
 // This runs on the window owner thread.
 void CreateWindowsOnThread(const gfx::Size& size,
                            base::WaitableEvent* event,
-                           SharedData* shared_data,
                            HWND* child_window,
                            HWND* parent_window) {
   InitializeWindowClass();
@@ -131,20 +91,25 @@ void CreateWindowsOnThread(const gfx::Size& size,
   // Create hidden parent window on the current thread.
   *parent_window = HiddenPopupWindow::Create();
   // Create child window.
+  // WS_EX_NOPARENTNOTIFY and WS_EX_LAYERED make the window transparent for
+  // input. WS_EX_NOREDIRECTIONBITMAP avoids allocating a
+  // bitmap that would otherwise be allocated with WS_EX_LAYERED, the bitmap is
+  // only necessary if using Gdi objects with the window.
   HWND window = CreateWindowEx(
-      WS_EX_NOPARENTNOTIFY, reinterpret_cast<wchar_t*>(g_window_class), L"",
+      WS_EX_NOPARENTNOTIFY | WS_EX_LAYERED | WS_EX_TRANSPARENT |
+          WS_EX_NOREDIRECTIONBITMAP,
+      reinterpret_cast<wchar_t*>(g_window_class), L"",
       WS_CHILDWINDOW | WS_DISABLED | WS_VISIBLE, 0, 0, size.width(),
       size.height(), *parent_window, nullptr, nullptr, nullptr);
   CHECK(window);
   *child_window = 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();
+void DestroyThread(std::unique_ptr<base::Thread> thread) {
+  thread->Stop();
 }
 
 // This runs on the window owner thread.
@@ -164,10 +129,9 @@ bool ChildWindowWin::Initialize() {
   if (window_)
     return true;
 
-  shared_data_ = std::make_unique<SharedData>();
-
+  thread_ = std::make_unique<base::Thread>("Window owner thread");
   base::Thread::Options options(base::MessageLoop::TYPE_UI, 0);
-  shared_data_->thread.StartWithOptions(options);
+  thread_->StartWithOptions(options);
 
   base::WaitableEvent event(base::WaitableEvent::ResetPolicy::AUTOMATIC,
                             base::WaitableEvent::InitialState::NOT_SIGNALED);
@@ -175,44 +139,30 @@ bool ChildWindowWin::Initialize() {
   RECT window_rect;
   GetClientRect(parent_window_, &window_rect);
 
-  shared_data_->thread.task_runner()->PostTask(
+  thread_->task_runner()->PostTask(
       FROM_HERE,
       base::Bind(&CreateWindowsOnThread, gfx::Rect(window_rect).size(), &event,
-                 shared_data_.get(), &window_, &initial_parent_window_));
+                 &window_, &initial_parent_window_));
   event.Wait();
 
   delegate_->DidCreateAcceleratedSurfaceChildWindow(parent_window_, window_);
   return true;
 }
 
-void ChildWindowWin::ClearInvalidContents() {
-  base::AutoLock lock(shared_data_->rect_lock);
-  if (!shared_data_->rect_to_clear.IsEmpty()) {
-    base::win::ScopedGetDC dc(window_);
-
-    RECT rect = shared_data_->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();
-  }
-}
-
 ChildWindowWin::~ChildWindowWin() {
-  if (shared_data_) {
-    scoped_refptr<base::TaskRunner> task_runner =
-        shared_data_->thread.task_runner();
+  if (thread_) {
+    scoped_refptr<base::TaskRunner> task_runner = thread_->task_runner();
     task_runner->PostTaskAndReply(
         FROM_HERE,
-        base::Bind(&DestroyWindowsOnThread, window_, initial_parent_window_),
-        base::Bind(&DestroySharedData, base::Passed(std::move(shared_data_))));
+        base::BindOnce(&DestroyWindowsOnThread, window_,
+                       initial_parent_window_),
+        base::BindOnce(&DestroyThread, base::Passed(std::move(thread_))));
   }
 }
 
 scoped_refptr<base::TaskRunner> ChildWindowWin::GetTaskRunnerForTesting() {
-  DCHECK(shared_data_);
-  return shared_data_->thread.task_runner();
+  DCHECK(thread_);
+  return thread_->task_runner();
 }
 
 }  // namespace gpu

gpu/ipc/service/child_window_win.h

@@ -7,14 +7,13 @@
 
 #include "base/memory/weak_ptr.h"
 #include "base/task_runner.h"
+#include "base/threading/thread.h"
 #include "gpu/ipc/service/image_transport_surface_delegate.h"
 
 #include <windows.h>
 
 namespace gpu {
 
-struct SharedData;
-
 // The window DirectComposition renders into needs to be owned by the process
 // that's currently doing the rendering. The class creates and owns a window
 // which is reparented by the browser to be a child of its window.
@@ -25,15 +24,13 @@ class ChildWindowWin {
   ~ChildWindowWin();
 
   bool Initialize();
-  void ClearInvalidContents();
   HWND window() const { return window_; }
 
   scoped_refptr<base::TaskRunner> GetTaskRunnerForTesting();
 
  private:
-  // This member contains all the data that can be accessed from the main or
-  // window owner threads.
-  std::unique_ptr<SharedData> shared_data_;
+  // The window owner thread.
+  std::unique_ptr<base::Thread> thread_;
   // The eventual parent of the window living in the browser process.
   HWND parent_window_;
   HWND window_;

gpu/ipc/service/direct_composition_surface_win.cc

@@ -1778,7 +1778,6 @@ gfx::SwapResult DirectCompositionSurfaceWin::SwapBuffers(
     const PresentationCallback& callback) {
   gl::GLSurfacePresentationHelper::ScopedSwapBuffers scoped_swap_buffers(
       presentation_helper_.get(), callback);
-  child_window_.ClearInvalidContents();
 
   bool succeeded = true;
   DCHECK(root_surface_);