Improve scroll performance on Windows 10 with high precision touchpads.

ui/gfx/win/direct_manipulation.cc

+// 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.
+
+#include "ui/gfx/win/direct_manipulation.h"
+
+#include "base/basictypes.h"
+#include "base/win/windows_version.h"
+
+namespace gfx {
+namespace win {
+
+// static
+DirectManipulationHelper* DirectManipulationHelper::CreateInstance() {
+  if (base::win::GetVersion() >= base::win::VERSION_WIN10)
+    return new DirectManipulationHelper;
+  return NULL;

[sky, 2015/08/11 23:45:02]

nullptr

[ananta, 2015/08/12 00:41:58]

Not needed anymore with the function returning a scoped ptr

+}
+
+void DirectManipulationHelper::Initialize(HWND window) {
+  DCHECK(::IsWindow(window));
+
+  // TODO(ananta)
+  // Remove the CHECK statements here and below and replace them with logs
+  // when this code stabilizes.
+  HRESULT hr = manager_.CreateInstance(CLSID_DirectManipulationManager,
+    nullptr, CLSCTX_INPROC_SERVER);
+  CHECK(SUCCEEDED(hr));
+
+  hr = compositor_.CreateInstance(CLSID_DCompManipulationCompositor,
+      nullptr, CLSCTX_INPROC_SERVER);
+  CHECK(SUCCEEDED(hr));
+
+  hr = manager_->GetUpdateManager(IID_PPV_ARGS(update_manager_.Receive()));
+  CHECK(SUCCEEDED(hr));
+
+  hr = compositor_->SetUpdateManager(update_manager_.get());
+  CHECK(SUCCEEDED(hr));
+
+  hr = frame_info_.QueryFrom(compositor_.get());
+  CHECK(SUCCEEDED(hr));
+
+  hr = manager_->CreateViewport(frame_info_.get(), window,
+      IID_PPV_ARGS(view_port_outer_.Receive()));
+  CHECK(SUCCEEDED(hr));
+
+  //
+  // Enable the desired configuration for each viewport.
+  //
+  DIRECTMANIPULATION_CONFIGURATION configuration =
+      DIRECTMANIPULATION_CONFIGURATION_INTERACTION
+      | DIRECTMANIPULATION_CONFIGURATION_TRANSLATION_X
+      | DIRECTMANIPULATION_CONFIGURATION_TRANSLATION_Y
+      | DIRECTMANIPULATION_CONFIGURATION_TRANSLATION_INERTIA
+      | DIRECTMANIPULATION_CONFIGURATION_RAILS_X
+      | DIRECTMANIPULATION_CONFIGURATION_RAILS_Y
+      | DIRECTMANIPULATION_CONFIGURATION_SCALING
+      | DIRECTMANIPULATION_CONFIGURATION_SCALING_INERTIA;
+
+  hr = view_port_outer_->ActivateConfiguration(configuration);
+  CHECK(SUCCEEDED(hr));
+}
+
+void DirectManipulationHelper::SetBounds(const gfx::Rect& bounds) {
+  base::win::ScopedComPtr<IDirectManipulationPrimaryContent>
+      primary_content_outer;
+  HRESULT hr = view_port_outer_->GetPrimaryContent(
+      IID_PPV_ARGS(primary_content_outer.Receive()));
+  CHECK(SUCCEEDED(hr));
+
+  base::win::ScopedComPtr<IDirectManipulationContent> content_outer;
+  hr = content_outer.QueryFrom(primary_content_outer.get());
+  CHECK(SUCCEEDED(hr));
+
+  RECT rect = bounds.ToRECT();
+
+  hr = view_port_outer_->SetViewportRect(&rect);
+  CHECK(SUCCEEDED(hr));
+
+  hr = content_outer->SetContentRect(&rect);
+  CHECK(SUCCEEDED(hr));
+}
+
+void DirectManipulationHelper::Activate(HWND window) {
+  DCHECK(::IsWindow(window));
+  HRESULT hr = manager_->Activate(window);
+  CHECK(SUCCEEDED(hr));
+}
+
+void DirectManipulationHelper:: HandleMouseWheel(HWND window, UINT message,
+    WPARAM w_param, LPARAM l_param) {
+  MSG msg = { window, message, w_param, l_param};
+
+  HRESULT hr = view_port_outer_->SetContact(DIRECTMANIPULATION_MOUSEFOCUS);
+  if (SUCCEEDED(hr)) {
+    BOOL handled = FALSE;
+    manager_->ProcessInput(&msg, &handled);
+    view_port_outer_->ReleaseContact(DIRECTMANIPULATION_MOUSEFOCUS);
+  }
+}
+
+}  // namespace win.
+}  // namespace gfx.