Centralizes snap sizing and implements spec'd behavior. Three resize

ash/wm/workspace/workspace_window_resizer.h

Index: ash/wm/workspace/workspace_window_resizer.h
diff --git a/ash/wm/workspace/workspace_window_resizer.h b/ash/wm/workspace/workspace_window_resizer.h
index eaa2b1d79475c287eace17be1e224cf13ad0f451..db2202e08656c850f2aeb5ec0b3a7f920134c78a 100644
--- a/ash/wm/workspace/workspace_window_resizer.h
+++ b/ash/wm/workspace/workspace_window_resizer.h
@@ -17,6 +17,7 @@ namespace internal {
 
 class PhantomWindowController;
 class RootWindowEventFilter;
+class SnapSizer;
 
 // WindowResizer implementation for workspaces. This enforces that windows are
 // not allowed to vertically move or resize outside of the work area. As windows
@@ -25,25 +26,13 @@ class RootWindowEventFilter;
 // attempt to restore the old height.
 class ASH_EXPORT WorkspaceWindowResizer : public WindowResizer {
  public:
-  // Used when the window is dragged against the edge of the screen.
-  enum EdgeType {
-    LEFT_EDGE,
-    RIGHT_EDGE
-  };
-
   // When dragging an attached window this is the min size we'll make sure is
-  // visibile. In the vertical direction we take the max of this and that from
+  // visible. In the vertical direction we take the max of this and that from
   // the delegate.
   static const int kMinOnscreenSize;
 
   virtual ~WorkspaceWindowResizer();
 
-  // Returns the bounds for a window along the specified edge.
-  static gfx::Rect GetBoundsForWindowAlongEdge(
-      aura::Window* window,
-      EdgeType edge,
-      int grid_size);
-
   static WorkspaceWindowResizer* Create(
       aura::Window* window,
       const gfx::Point& location,
@@ -68,21 +57,17 @@ class ASH_EXPORT WorkspaceWindowResizer : public WindowResizer {
                          const std::vector<aura::Window*>& attached_windows);
 
  private:
-  // Location of the phanton window.
-  enum PhantomType {
-    TYPE_LEFT_EDGE,
-    TYPE_RIGHT_EDGE,
-    TYPE_DESTINATION,
-    TYPE_NONE
-  };
+  // Type of snapping.
+  enum SnapType {
+    // Snap to the left/right edge of the screen.
+    SNAP_LEFT_EDGE,
+    SNAP_RIGHT_EDGE,
 
-  // Type and bounds of the phantom window.
-  struct PhantomPlacement {
-    PhantomPlacement();
-    ~PhantomPlacement();
+    // Snap to the final bounds. Used when there is a grid.
+    SNAP_DESTINATION,
 
-    PhantomType type;
-    gfx::Rect bounds;
+    // No snap position.
+    SNAP_NONE
   };
 
   // Returns the final bounds to place the window at. This differs from
@@ -116,14 +101,9 @@ class ASH_EXPORT WorkspaceWindowResizer : public WindowResizer {
   // Updates the bounds of the phantom window.
   void UpdatePhantomWindow(const gfx::Point& location);
 
-  // Updates |phantom_placement_| when type is one of TYPE_LEFT_EDGE or
-  // TYPE_RIGHT_EDGE.
-  void UpdatePhantomWindowBoundsAlongEdge(
-      const PhantomPlacement& last_placement);
-
-  // Returns a PhantomPlacement for the specified point. TYPE_NONE is used if
-  // the location doesn't have a valid phantom location.
-  PhantomPlacement GetPhantomPlacement(const gfx::Point& location);
+  // Returns the SnapType for the specified point. SNAP_NONE is used if no
+  // snapping should be used.
+  SnapType GetSnapType(const gfx::Point& location) const;
 
   aura::Window* window() const { return details_.window; }
 
@@ -162,8 +142,11 @@ class ASH_EXPORT WorkspaceWindowResizer : public WindowResizer {
   // is a grid and the caption is being dragged.
   scoped_ptr<PhantomWindowController> phantom_window_controller_;
 
-  // Last PhantomPlacement.
-  PhantomPlacement phantom_placement_;
+  // Used to determine the target position of a snap.
+  scoped_ptr<SnapSizer> snap_sizer_;
+
+  // Last SnapType.
+  SnapType snap_type_;
 
   // Number of mouse moves since the last bounds change. Only used for phantom
   // placement to track when the mouse is moved while pushed against the edge of