Make touch-resizing windows to screen edge possible

ash/wm/workspace/workspace_window_resizer.cc

Index: ash/wm/workspace/workspace_window_resizer.cc
diff --git a/ash/wm/workspace/workspace_window_resizer.cc b/ash/wm/workspace/workspace_window_resizer.cc
index 25430933827c63762fb0e9b7dcc1cc1d348f5370..710eaad3f10c2bae279b97f6ff755cfe60f513ee 100644
--- a/ash/wm/workspace/workspace_window_resizer.cc
+++ b/ash/wm/workspace/workspace_window_resizer.cc
@@ -36,9 +36,11 @@
 
 namespace ash {
 
-scoped_ptr<WindowResizer> CreateWindowResizer(aura::Window* window,
-                                              const gfx::Point& point_in_parent,
-                                              int window_component) {
+scoped_ptr<WindowResizer> CreateWindowResizer(
+    aura::Window* window,
+    const gfx::Point& point_in_parent,
+    int window_component,
+    aura::client::WindowMoveSource source) {
   DCHECK(window);
   // No need to return a resizer when the window cannot get resized.
   if (!wm::CanResizeWindow(window) && window_component != HTCAPTION)
@@ -56,18 +58,19 @@ scoped_ptr<WindowResizer> CreateWindowResizer(aura::Window* window,
         window,
         point_in_parent,
         window_component,
+        source,
         std::vector<aura::Window*>());
   } else if (wm::IsWindowNormal(window)) {
     window_resizer = DefaultWindowResizer::Create(
-        window, point_in_parent, window_component);
+        window, point_in_parent, window_component, source);
   }
   if (window_resizer) {
     window_resizer = internal::DragWindowResizer::Create(
-        window_resizer, window, point_in_parent, window_component);
+        window_resizer, window, point_in_parent, window_component, source);
   }
   if (window_resizer && window->type() == aura::client::WINDOW_TYPE_PANEL) {
     window_resizer = PanelWindowResizer::Create(
-        window_resizer, window, point_in_parent, window_component);
+        window_resizer, window, point_in_parent, window_component, source);
   }
   return make_scoped_ptr<WindowResizer>(window_resizer);
 }
@@ -80,6 +83,10 @@ namespace {
 // to move or resize beyond that edge.
 const int kStickyDistancePixels = 64;
 
+// Snapping distance used instead of WorkspaceWindowResizer::kScreenEdgeInset
+// when resizing a window using touchscreen.
+const int kScreenEdgeInsetForTouchResize = 16;

[sky, 2013/06/14 15:57:27]

I thought we were going to make this 32?

[mohsen, 2013/06/14 16:21:48]

32 was for the case that we only wanted to use snapping. But now that we align
border immediately with touch, 16 is enough. But, we can change it to 32 if you
think that's better?

[sky, 2013/06/14 16:25:07]

I only mention it since I thought we agreed on 32 in the email thread. Maybe I'm
wrong?

[mohsen, 2013/06/14 18:17:17]

Well, I thought that was for when we only have snapping. Anyway, I changed it
back to 32.

+
 // Returns true if the window should stick to the edge.
 bool ShouldStickToEdge(int distance_from_edge, int sticky_size) {
   if (CommandLine::ForCurrentProcess()->HasSwitch(
@@ -310,8 +317,9 @@ WorkspaceWindowResizer* WorkspaceWindowResizer::Create(
     aura::Window* window,
     const gfx::Point& location_in_parent,
     int window_component,
+    aura::client::WindowMoveSource source,
     const std::vector<aura::Window*>& attached_windows) {
-  Details details(window, location_in_parent, window_component);
+  Details details(window, location_in_parent, window_component, source);
   return details.is_resizable ?
       new WorkspaceWindowResizer(details, attached_windows) : NULL;
 }
@@ -326,6 +334,9 @@ void WorkspaceWindowResizer::Drag(const gfx::Point& location_in_parent,
   } else if (CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kAshEnableStickyEdges)) {
     sticky_size = kStickyDistancePixels;
+  } else if ((details_.bounds_change & kBoundsChange_Resizes) &&
+      details_.source == aura::client::WINDOW_MOVE_SOURCE_TOUCH) {
+    sticky_size = kScreenEdgeInsetForTouchResize;

[sky, 2013/06/14 15:57:27]

Do you want this only effect snapping to screen bounds?

[mohsen, 2013/06/14 16:21:48]

The problem only happens for resizing to the screen edge. Snapping to other
windows works with the current configuration. Do you think we have better be
consistent in both cases?

[sky, 2013/06/14 16:25:07]

My point is that doing the change here effects *all* cases, not just the one you
care about. I don't necessarily know if this is a problem. I'm just pointing it
out. It seems reasonable to increase the size for everything during touch, which
matches what you're doing here. But I don't know how that feels in practice. I
raise the issue to make sure you understand the impact of your change.

[mohsen, 2013/06/14 18:17:17]

I think this sticy_size is only used for snapping to screen edges. The one used
for other windows is MagnetismMathcer::kMagneticDistance
(https://code.google.com/p/chromium/codesearch#chromium/src/ash/wm/workspace/m...)
used here:
https://code.google.com/p/chromium/codesearch#chromium/src/ash/wm/workspace/m....
Also my tests show that this only affects snapping to screen edge.

[sky, 2013/06/14 19:22:22]

Ah yes, you are right. Sorry about that.

   } else {
     sticky_size = kScreenEdgeInset;
   }