Makes windows scale slightly when dragging the caption. Also wired

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 a16178cf6c68fdac09e2f5f11cc7801bd770df74..699617fe82ecc3fb21a93df0936de08772d4225b 100644
--- a/ash/wm/workspace/workspace_window_resizer.cc
+++ b/ash/wm/workspace/workspace_window_resizer.cc
@@ -7,7 +7,11 @@
 #include "ui/aura/window.h"
 #include "ui/aura/window_delegate.h"
 #include "ui/aura/window_property.h"
+#include "ui/base/hit_test.h"
+#include "ui/gfx/compositor/scoped_layer_animation_settings.h"
+#include "ui/gfx/compositor/layer.h"
 #include "ui/gfx/screen.h"
+#include "ui/gfx/transform.h"
 
 DECLARE_WINDOW_PROPERTY_TYPE(int)
 
@@ -22,21 +26,78 @@ const aura::WindowProperty<int>* const kHeightBeforeObscuredKey =
 
 }  // namespace
 
+// static
+bool WorkspaceWindowResizer::scale_windows_ = true;
+
 WorkspaceWindowResizer::WorkspaceWindowResizer(aura::Window* window,
                                                const gfx::Point& location,
                                                int window_component,
                                                int grid_size)
-    : WindowResizer(window, location, window_component, grid_size) {
+    : WindowResizer(window, location, window_component, grid_size),
+      scale_window_(scale_windows_ && is_resizable() &&
+                    window_component == HTCAPTION) {
   if (is_resizable() && GetHeightBeforeObscured(window) &&
       (!WindowTouchesBottomOfScreen() ||
        bounds_change() != kBoundsChange_Repositions)) {
     ClearHeightBeforeObscured(window);
   }
+  if (scale_window_) {
+    // When dragging the caption scale slightly from the center.
+    float scale = 1.01f;
+    float x_offset =
+        static_cast<float>(window->bounds().width()) * (scale - 1) / 2.0f;
+    float y_offset =
+        (static_cast<float>(window->bounds().width()) * (scale - 1) / 2.0f);
+    ui::Transform transform;
+    transform.SetTranslate(-x_offset, -y_offset);
+    transform.SetScaleX(scale);
+    transform.SetScaleY(scale);
+    window->layer()->SetTransform(transform);
+  }
 }
 
 WorkspaceWindowResizer::~WorkspaceWindowResizer() {
 }
 
+// static
+void WorkspaceWindowResizer::SetScaleWindowsForTest(bool value) {
+  scale_windows_ = value;
+}
+
+void WorkspaceWindowResizer::CompleteDrag() {
+  if (!did_move_or_resize() || grid_size() <= 1) {
+    if (scale_window_) {
+      ui::ScopedLayerAnimationSettings scoped_setter(
+          window()->layer()->GetAnimator());
+      window()->layer()->SetTransform(ui::Transform());
+    }
+    return;
+  }
+
+  gfx::Rect new_bounds(GetFinalBounds());
+  if (new_bounds.size() != window()->bounds().size()) {
+    // Don't attempt to animate a size change.
+    window()->SetBounds(new_bounds);
+    if (scale_window_)
+      window()->layer()->SetTransform(ui::Transform());
+    return;
+  }
+
+  ui::ScopedLayerAnimationSettings scoped_setter(
+      window()->layer()->GetAnimator());
+  // Use a small duration since the grid is small.
+  scoped_setter.SetTransitionDuration(base::TimeDelta::FromMilliseconds(100));
+  window()->SetBounds(new_bounds);
+  if (scale_window_)
+    window()->layer()->SetTransform(ui::Transform());
+}
+
+void WorkspaceWindowResizer::RevertDrag() {
+  if (scale_window_)
+    window()->layer()->SetTransform(ui::Transform());
+  WindowResizer::RevertDrag();
+}
+
 gfx::Rect WorkspaceWindowResizer::GetBoundsForDrag(const gfx::Point& location) {
   if (!is_resizable())
     return WindowResizer::GetBoundsForDrag(location);