touch: Cleanup touch-event mode switching on windows.

content/browser/renderer_host/render_widget_host_view_win.cc

 // Copyright (c) 2012 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 "content/browser/renderer_host/render_widget_host_view_win.h"
 
 #include <algorithm>
 #include <map>
 #include <peninputpanel_i.c>
 #include <stack>
@@ skipping 933 matching lines @@
       output->getTopDevice()->accessBitmap(true).getPixels());
   scoped_callback_runner.Release();
   callback.Run(result);
 }
 
 void RenderWidgetHostViewWin::SetBackground(const SkBitmap& background) {
   RenderWidgetHostViewBase::SetBackground(background);
   render_widget_host_->SetBackground(background);
 }
 
-void RenderWidgetHostViewWin::ProcessTouchAck(
-    WebKit::WebInputEvent::Type type, bool processed) {
+void RenderWidgetHostViewWin::ProcessTouchAck(bool processed) {
 
   DCHECK(render_widget_host_->has_touch_handler() &&
       touch_events_enabled_);
 
   int touch_count = touch_state_->GetNextTouchCount();
   for (int i = 0; i < touch_count; ++i) {
     scoped_ptr<ui::GestureRecognizer::Gestures> gestures;
     gestures.reset(gesture_recognizer_->AdvanceTouchQueue(this, processed));
     ProcessGestures(gestures.get());
   }
-
-  if (type == WebKit::WebInputEvent::TouchStart)
-    UpdateDesiredTouchMode(processed);
 }
 
 void RenderWidgetHostViewWin::SetToGestureMode() {
   if (base::win::GetVersion() < base::win::VERSION_WIN7)
     return;
   UnregisterTouchWindow(m_hWnd);
   // Single finger panning is consistent with other windows applications.
   const DWORD gesture_allow = GC_PAN_WITH_SINGLE_FINGER_VERTICALLY |
                               GC_PAN_WITH_SINGLE_FINGER_HORIZONTALLY;
   const DWORD gesture_block = GC_PAN_WITH_GUTTER;
@@ skipping 11 matching lines @@
 }
 
 bool RenderWidgetHostViewWin::SetToTouchMode() {
   if (base::win::GetVersion() < base::win::VERSION_WIN7)
     return false;
   bool touch_mode = RegisterTouchWindow(m_hWnd, TWF_WANTPALM) == TRUE;
   touch_events_enabled_ = touch_mode;
   return touch_mode;
 }
 
-void RenderWidgetHostViewWin::UpdateDesiredTouchMode(bool touch_mode) {
+void RenderWidgetHostViewWin::UpdateDesiredTouchMode() {

[scottmg, 2012/10/11 16:58:53]

could probably be simplified a  bit more, since it's only called OnCreate now?

[sadrul, 2012/10/11 17:02:09]

Perhaps. What simplification did you have in mind?

[scottmg, 2012/10/11 17:09:29]

Sorry, wasn't trying to be the riddler...

- SetToTouchMode could be inlined since there's only 2 work lines and the WIN7
guard is redundant
- the if ((touch_mode && ...) || (!touch_mode ...)) can be replaced with just
!touch_mode
- Is touch_events_enabled_ even required any more? (only ref'd in Cancel)

[sadrul, 2012/10/11 17:25:10]

Ah, indeed. I have made the following changes:
 - Moved code from SetToTouchMode and SetToGestureMode into
UpdateDesiredTouchMode
 - simplified the 'if ((touch_mode...' check as you suggested

I have kept touch_events_enabled_ though, since it looks like it may be possible
that RegisterTouchWindow() may not always return TRUE (and used to check whether
or not to send fake-mouse-events-from-touch to the renderer).

   // Make sure that touch events even make sense.
-  bool touch_mode_valid = base::win::GetVersion() >= base::win::VERSION_WIN7 &&
+  bool touch_mode = base::win::GetVersion() >= base::win::VERSION_WIN7 &&
       CommandLine::ForCurrentProcess()->HasSwitch(switches::kEnableTouchEvents);
-  touch_mode = touch_mode_valid;
 
   // Already in correct mode, nothing to do.
   if ((touch_mode && touch_events_enabled_) ||
       (!touch_mode && !touch_events_enabled_))
     return;
 
   // Now we know that the window's current state doesn't match the desired
   // state. If we want touch mode, then we attempt to register for touch
   // events, and otherwise to unregister.
-  if (touch_mode) {
+  if (touch_mode)
     touch_mode = SetToTouchMode();
-  }
-  if (!touch_mode) {
+  if (!touch_mode)
     SetToGestureMode();
-  }
 }
 
 bool RenderWidgetHostViewWin::DispatchLongPressGestureEvent(
     ui::GestureEvent* event) {
   return ForwardGestureEventToRenderer(event);
 }
 
 bool RenderWidgetHostViewWin::DispatchCancelTouchEvent(
     ui::TouchEvent* event) {
   if (!render_widget_host_ || !touch_events_enabled_)
@@ skipping 233 matching lines @@
 
 LRESULT RenderWidgetHostViewWin::OnCreate(CREATESTRUCT* create_struct) {
   TRACE_EVENT0("browser", "RenderWidgetHostViewWin::OnCreate");
   // Call the WM_INPUTLANGCHANGE message handler to initialize the input locale
   // of a browser process.
   OnInputLangChange(0, 0);
   // Marks that window as supporting mouse-wheel messages rerouting so it is
   // scrolled when under the mouse pointer even if inactive.
   props_.push_back(ui::SetWindowSupportsRerouteMouseWheel(m_hWnd));
 
-  bool touch_enabled = base::win::GetVersion() >= base::win::VERSION_WIN7 &&
-      CommandLine::ForCurrentProcess()->HasSwitch(switches::kEnableTouchEvents);
-  if (touch_enabled)
-    SetToTouchMode();
-  else
-    SetToGestureMode();
-
+  UpdateDesiredTouchMode();
   UpdateIMEState();
 
   return 0;
 }
 
 void RenderWidgetHostViewWin::OnActivate(UINT action, BOOL minimized,
                                          HWND window) {
   TRACE_EVENT0("browser", "RenderWidgetHostViewWin::OnActivate");
   // If the container is a popup, clicking elsewhere on screen should close the
   // popup.
@@ skipping 1840 matching lines @@
   // receive a focus change in the context of a pointer down message, it means
   // that the pointer down message occurred on the edit field and we should
   // display the on screen keyboard
   if (!received_focus_change_after_pointer_down_ && virtual_keyboard_)
     DisplayOnScreenKeyboardIfNeeded();
   received_focus_change_after_pointer_down_ = false;
   pointer_down_context_ = false;
 }
 
 }  // namespace content