Initial cut at multi-window resize code. There's still some TODOs, but

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 e881202ab96262c00dca245147cbf97f5057b457..741084682b6a7266a90d9463e99a83d363847c50 100644
--- a/ash/wm/workspace/workspace_window_resizer.h
+++ b/ash/wm/workspace/workspace_window_resizer.h
@@ -6,6 +6,8 @@
 #define ASH_WM_WORKSPACE_WINDOW_RESIZER_H_
 #pragma once
 
+#include <vector>
+
 #include "ash/wm/window_resizer.h"
 #include "base/compiler_specific.h"
 
@@ -21,15 +23,19 @@ class RootWindowEventFilter;
 // attempt to restore the old height.
 class ASH_EXPORT WorkspaceWindowResizer : public WindowResizer {
  public:
+  // 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
+  // the delegate.
+  static const int kMinOnscreenSize;
+
   virtual ~WorkspaceWindowResizer();
 
-  // Creates a new WorkspaceWindowResizer. The caller takes ownership of the
-  // returned object. Returns NULL if not resizable.
   static WorkspaceWindowResizer* Create(
       aura::Window* window,
       const gfx::Point& location,
       int window_component,
-      int grid_size);
+      int grid_size,
+      const std::vector<aura::Window*>& attached_windows);
 
   // Returns true if the drag will result in changing the window in anyway.
   bool is_resizable() const { return details_.is_resizable; }
@@ -44,8 +50,16 @@ class ASH_EXPORT WorkspaceWindowResizer : public WindowResizer {
   virtual void RevertDrag() OVERRIDE;
 
  private:
+  WorkspaceWindowResizer(const Details& details,
+                         const std::vector<aura::Window*>& attached_windows);
+
+ private:
   explicit WorkspaceWindowResizer(const Details& details);
 
+  // Lays out the attached windows. |bounds| is the bounds of the main window.
+  void LayoutAttachedWindowsHorizontally(const gfx::Rect& bounds);
+  void LayoutAttachedWindowsVertically(const gfx::Rect& bounds);
+
   // Adjusts the bounds to enforce that windows are vertically contained in the
   // work area.
   void AdjustBoundsForMainWindow(gfx::Rect* bounds) const;
@@ -53,11 +67,18 @@ class ASH_EXPORT WorkspaceWindowResizer : public WindowResizer {
                              aura::Window* window,
                              gfx::Rect* bounds) const;
 
-  // Clears the cached height of the window being dragged.
+  // Clears the cached width/height of the window being dragged.
   void ClearCachedHeights();
+  void ClearCachedWidths();
 
-  // Returns true if the window touches the bottom of the work area.
+  // Returns true if the window touches the bottom/right edge of the work area.
   bool TouchesBottomOfScreen() const;
+  bool TouchesRightSideOfScreen() const;
+
+  // Returns a coordinate along the primary axis. Used to share code for
+  // left/right multi window resize and top/bottom resize.
+  int PrimaryAxisSize(const gfx::Size& size) const;
+  int PrimaryAxisCoordinate(int x, int y) const;
 
   aura::Window* window() const { return details_.window; }
 
@@ -66,11 +87,32 @@ class ASH_EXPORT WorkspaceWindowResizer : public WindowResizer {
   // True if the window size (height) should be constrained.
   const bool constrain_size_;
 
+  const std::vector<aura::Window*> attached_windows_;
+
   // Set to true once Drag() is invoked and the bounds of the window change.
   bool did_move_or_resize_;
 
   internal::RootWindowEventFilter* root_filter_;
 
+  // The initial size of each of the windows in |attached_windows_| along the
+  // primary axis.
+  std::vector<int> initial_size_;
+
+  // The min size of each of the windows in |attached_windows_| along the
+  // primary axis.
+  std::vector<int> min_size_;
+
+  // The amount each of the windows in |attached_windows_| can be compressed.
+  // This is a fraction of the amount a window can be compressed over the total
+  // space the windows can be compressed.
+  std::vector<float> compress_fraction_;
+
+  // Sum of sizes in |min_size_|.
+  int total_min_;
+
+  // Sum of the sizes in |initial_size_|.
+  int total_initial_size_;
+
   DISALLOW_COPY_AND_ASSIGN(WorkspaceWindowResizer);
 };