touch: Cleanup touch-event mode switching on windows.

content/browser/renderer_host/render_widget_host_view_win.cc

Index: content/browser/renderer_host/render_widget_host_view_win.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_win.cc b/content/browser/renderer_host/render_widget_host_view_win.cc
index e78a07e268c82ea13c9eb60c1a4e17693fd5cd87..d4f13293ba2e9231e7649f01cd09e99447ddc2be 100644
--- a/content/browser/renderer_host/render_widget_host_view_win.cc
+++ b/content/browser/renderer_host/render_widget_host_view_win.cc
@@ -951,8 +951,7 @@ void RenderWidgetHostViewWin::SetBackground(const SkBitmap& 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_);
@@ -963,9 +962,6 @@ void RenderWidgetHostViewWin::ProcessTouchAck(
     gestures.reset(gesture_recognizer_->AdvanceTouchQueue(this, processed));
     ProcessGestures(gestures.get());
   }
-
-  if (type == WebKit::WebInputEvent::TouchStart)
-    UpdateDesiredTouchMode(processed);
 }
 
 void RenderWidgetHostViewWin::SetToGestureMode() {
@@ -997,11 +993,10 @@ bool RenderWidgetHostViewWin::SetToTouchMode() {
   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_) ||
@@ -1011,12 +1006,10 @@ void RenderWidgetHostViewWin::UpdateDesiredTouchMode(bool touch_mode) {
   // 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(
@@ -1270,13 +1263,7 @@ LRESULT RenderWidgetHostViewWin::OnCreate(CREATESTRUCT* create_struct) {
   // 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;