touchui: Fine-tune selection-controller visibility.

This makes two changes:
 + Makes sure the selection bound has a minimum size before the controller is
   made visible.
 + Delays updating the touch-selection controller a little bit to account for the
   erroneous selection-change messages from webkit.

BUG=none
TEST=manually

Review URL: http://codereview.chromium.org/7778039

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@99894 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/renderer_host/render_widget_host_view_views.cc

@@ -43,6 +43,7 @@
 
 static const int kMaxWindowWidth = 4000;
 static const int kMaxWindowHeight = 4000;
+static const int kTouchControllerUpdateDelay = 150;
 
 // static
 const char RenderWidgetHostViewViews::kViewClassName[] =
@@ -95,7 +96,8 @@ RenderWidgetHostViewViews::RenderWidgetHostViewViews(RenderWidgetHost* host)
       text_input_type_(ui::TEXT_INPUT_TYPE_NONE),
       has_composition_text_(false),
       ALLOW_THIS_IN_INITIALIZER_LIST(touch_selection_controller_(
-          views::TouchSelectionController::create(this))) {
+          views::TouchSelectionController::create(this))),
+      ALLOW_THIS_IN_INITIALIZER_LIST(update_touch_selection_(this)) {
   set_focusable(true);
   host_->SetView(this);
 
@@ -156,10 +158,7 @@ void RenderWidgetHostViewViews::DidBecomeSelected() {
   if (host_)
     host_->WasRestored();
 
-  if (touch_selection_controller_.get()) {
-    touch_selection_controller_->SelectionChanged(selection_start_,
-                                                  selection_end_);
-  }
+  UpdateTouchSelectionController();
 }
 
 void RenderWidgetHostViewViews::WasHidden() {
@@ -176,6 +175,9 @@ void RenderWidgetHostViewViews::WasHidden() {
   if (host_)
     host_->WasHidden();
 
+  if (!update_touch_selection_.empty())
+    update_touch_selection_.RevokeAll();
+
   if (touch_selection_controller_.get())
     touch_selection_controller_->ClientViewLostFocus();
 }
@@ -346,8 +348,21 @@ void RenderWidgetHostViewViews::SelectionChanged(const std::string& text,
   NOTIMPLEMENTED();
   selection_start_ = start;
   selection_end_ = end;
-  if (touch_selection_controller_.get())
-    touch_selection_controller_->SelectionChanged(start, end);
+
+  // TODO(sad): This is a workaround for a webkit bug:
+  // https://bugs.webkit.org/show_bug.cgi?id=67464
+  // Remove this when the bug gets fixed.
+  //
+  // Webkit can send spurious selection-change on text-input (e.g. when
+  // inserting text at the beginning of a non-empty text control). But in those
+  // cases, it does send the correct selection information quickly afterwards.
+  // So delay the notification to the touch-selection controller.
+  if (update_touch_selection_.empty()) {
+    MessageLoop::current()->PostDelayedTask(FROM_HERE,
+        update_touch_selection_.NewRunnableMethod(
+          &RenderWidgetHostViewViews::UpdateTouchSelectionController),
+        kTouchControllerUpdateDelay);
+  }
 }
 
 void RenderWidgetHostViewViews::ShowingContextMenu(bool showing) {
@@ -816,3 +831,9 @@ void RenderWidgetHostViewViews::FinishImeCompositionSession() {
   GetInputMethod()->CancelComposition(this);
   has_composition_text_ = false;
 }
+
+void RenderWidgetHostViewViews::UpdateTouchSelectionController() {
+  if (touch_selection_controller_.get())
+    touch_selection_controller_->SelectionChanged(selection_start_,
+                                                  selection_end_);
+}

chrome/browser/renderer_host/render_widget_host_view_views.h

@@ -205,6 +205,10 @@ class RenderWidgetHostViewViews : public RenderWidgetHostView,
   // to cancel its ongoing composition sesstion.
   void FinishImeCompositionSession();
 
+  // Updates the touch-selection controller (e.g. when the selection/focus
+  // changes).
+  void UpdateTouchSelectionController();
+
 #if defined(TOOLKIT_USES_GTK)
   // On some systems, there can be two native views, where an outer native view
   // contains the inner native view (e.g. when using GTK+). This returns the
@@ -271,6 +275,8 @@ class RenderWidgetHostViewViews : public RenderWidgetHostView,
   scoped_ptr<views::TouchSelectionController> touch_selection_controller_;
   gfx::Point selection_start_;
   gfx::Point selection_end_;
+  ScopedRunnableMethodFactory<RenderWidgetHostViewViews>
+      update_touch_selection_;
 
 #if defined(TOUCH_UI)
   std::map<uint64, scoped_refptr<AcceleratedSurfaceContainerTouch> >

views/touchui/touch_selection_controller_impl.cc

@@ -31,6 +31,9 @@ const int kSelectionHandleAlpha = 0x7F;
 const SkColor kSelectionHandleColor =
     SkColorSetA(SK_ColorBLUE, kSelectionHandleAlpha);
 
+// The minimum selection size to trigger selection controller.
+const int kMinSelectionSize = 4;
+
 const int kContextMenuCommands[] = {IDS_APP_CUT,
                                     IDS_APP_COPY,
 // TODO(varunjain): PASTE is acting funny due to some gtk clipboard issue.
@@ -78,6 +81,15 @@ void PaintCircle(const Circle& circle, gfx::Canvas* canvas) {
   canvas->AsCanvasSkia()->drawPath(path, paint);
 }
 
+// The points may not match exactly, since the selection range computation may
+// introduce some floating point errors. So check for a minimum size to decide
+// whether or not there is any selection.
+bool IsEmptySelection(const gfx::Point& p1, const gfx::Point& p2) {
+  int delta_x = p2.x() - p1.x();
+  int delta_y = p2.y() - p1.y();
+  return (abs(delta_x) < kMinSelectionSize && abs(delta_y) < kMinSelectionSize);
+}
+
 }  // namespace
 
 namespace views {
@@ -278,7 +290,7 @@ void TouchSelectionControllerImpl::SelectionChanged(const gfx::Point& p1,
     UpdateContextMenu(p1, p2);
 
     // Check if there is any selection at all.
-    if (screen_pos_1 == screen_pos_2) {
+    if (IsEmptySelection(screen_pos_2, screen_pos_1)) {
       selection_handle_1_->SetVisible(false);
       selection_handle_2_->SetVisible(false);
       return;
@@ -386,7 +398,7 @@ void TouchSelectionControllerImpl::UpdateContextMenu(const gfx::Point& p1,
   HideContextMenu();
 
   // If there is selection, we restart the context menu timer.
-  if (p1 != p2) {
+  if (!IsEmptySelection(p1, p2)) {
     context_menu_timer_.Start(
         FROM_HERE,
         base::TimeDelta::FromMilliseconds(kContextMenuTimoutMs),