Support for Adaptive Handle Orientation

ui/touch_selection/touch_selection_controller.cc

Index: ui/touch_selection/touch_selection_controller.cc
diff --git a/ui/touch_selection/touch_selection_controller.cc b/ui/touch_selection/touch_selection_controller.cc
index 2e18037c658c9b0f7fc02d66e5a8471e8589d0a2..4c02867187a5ca59ad2c53f252b63db60504c67b 100644
--- a/ui/touch_selection/touch_selection_controller.cc
+++ b/ui/touch_selection/touch_selection_controller.cc
@@ -11,9 +11,12 @@
 namespace ui {
 namespace {
 
-gfx::Vector2dF ComputeLineOffsetFromBottom(const SelectionBound& bound) {
-  gfx::Vector2dF line_offset =
-      gfx::ScaleVector2d(bound.edge_top() - bound.edge_bottom(), 0.5f);
+gfx::Vector2dF ComputeLineOffsetFromBottom(const SelectionBound& bound,
+                                           bool compute_from_top) {
+  gfx::Vector2dF vertical_offset =
+      compute_from_top ? (bound.edge_bottom() - bound.edge_top())
+                       : (bound.edge_top() - bound.edge_bottom());
+  gfx::Vector2dF line_offset = gfx::ScaleVector2d(vertical_offset, 0.5f);
   // An offset of 5 DIPs is sufficient for most line sizes. For small lines,
   // using half the line height avoids synthesizing a point on a line above
   // (or below) the intended line.
@@ -59,6 +62,7 @@ TouchSelectionController::TouchSelectionController(
       selection_empty_(false),
       selection_editable_(false),
       temporarily_hidden_(false),
+      viewport_size_changed_(false),
       selection_handle_dragged_(false) {
   DCHECK(client_);
 }
@@ -66,16 +70,25 @@ TouchSelectionController::TouchSelectionController(
 TouchSelectionController::~TouchSelectionController() {
 }
 
+void TouchSelectionController::OnViewportChanged(
+    const gfx::RectF viewport_rect) {
+  if (viewport_rect_ == viewport_rect)
+    return;
+  viewport_size_changed_ = true;
+  viewport_rect_ = viewport_rect;
+}
+
 void TouchSelectionController::OnSelectionBoundsChanged(
     const SelectionBound& start,
     const SelectionBound& end) {
-  if (start == start_ && end_ == end)
+  if (start == start_ && end_ == end && !viewport_size_changed_)
     return;
 
   start_ = start;
   end_ = end;
   start_orientation_ = ToTouchHandleOrientation(start_.type());
   end_orientation_ = ToTouchHandleOrientation(end_.type());
+  viewport_size_changed_ = false;
 
   if (!activate_selection_automatically_ &&
       !activate_insertion_automatically_) {
@@ -381,14 +394,16 @@ void TouchSelectionController::ActivateSelection() {
     start_selection_handle_.reset(new TouchHandle(this, start_orientation_));
   } else {
     start_selection_handle_->SetEnabled(true);
-    start_selection_handle_->SetOrientation(start_orientation_);
+    start_selection_handle_->SetOrientation(start_orientation_, viewport_rect_,
+                                            start_.edge_bottom());
   }
 
   if (!end_selection_handle_) {
     end_selection_handle_.reset(new TouchHandle(this, end_orientation_));
   } else {
     end_selection_handle_->SetEnabled(true);
-    end_selection_handle_->SetOrientation(end_orientation_);
+    end_selection_handle_->SetOrientation(end_orientation_, viewport_rect_,
+                                          end_.edge_bottom());
   }
 
   // As a long press received while a selection is already active may trigger
@@ -429,19 +444,27 @@ void TouchSelectionController::ResetCachedValuesIfInactive() {
 }
 
 const gfx::PointF& TouchSelectionController::GetStartPosition() const {
+  if (start_selection_handle_ && start_selection_handle_->is_inverted())
+    return start_.edge_top();
   return start_.edge_bottom();
 }
 
 const gfx::PointF& TouchSelectionController::GetEndPosition() const {
+  if (end_selection_handle_ && end_selection_handle_->is_inverted())
+    return end_.edge_top();
   return end_.edge_bottom();
 }
 
 gfx::Vector2dF TouchSelectionController::GetStartLineOffset() const {
-  return ComputeLineOffsetFromBottom(start_);
+  DCHECK(start_selection_handle_);
+  bool compute_from_top = start_selection_handle_->is_inverted();
+  return ComputeLineOffsetFromBottom(start_, compute_from_top);
 }
 
 gfx::Vector2dF TouchSelectionController::GetEndLineOffset() const {
-  return ComputeLineOffsetFromBottom(end_);
+  DCHECK(end_selection_handle_);
+  bool compute_from_top = end_selection_handle_->is_inverted();
+  return ComputeLineOffsetFromBottom(end_, compute_from_top);
 }
 
 bool TouchSelectionController::GetStartVisible() const {