Omnibox UI Experiments: Refine steady state elision for double-click

Previously, for double-click partial selections, the partial select
took place on mousedown, and the unelision took place on mouseup.

This CL makes them both take place on mousedown, to (hopefully) reduce
the visual noise.

Bug: 797354
Change-Id: I7a7d26740ffeef028a368a9d3b467c54674b8a83
Reviewed-on: https://chromium-review.googlesource.com/935828Reviewed-by: Justin Donnelly <jdonnelly@chromium.org>
Commit-Queue: Tommy Li <tommycli@chromium.org>
Cr-Commit-Position: refs/heads/master@{#538979}

chrome/browser/ui/views/omnibox/omnibox_view_views.cc

@@ -528,10 +528,6 @@ bool OmniboxViewViews::UnapplySteadyStateElisions() {
     return false;
   }
 
-  // If the mouse is pressed, we defer this operation until mouseup.
-  if (is_mouse_pressed_)
-    return false;
-
   // No need to update the text if the user is already inputting text or if
   // everything is selected.
   if (model()->user_input_in_progress() || IsSelectAll())
@@ -580,8 +576,11 @@ bool OmniboxViewViews::OnAfterPossibleChange(bool allow_keyword_ui_change) {
   bool something_changed = model()->OnAfterPossibleChange(
       state_changes, allow_keyword_ui_change && !IsIMEComposing());
 
-  // If any mouse button is pressed, we defer this operation until mouseup.
-  if (UnapplySteadyStateElisions()) {
+  // Unapply steady state elisions in response to selection changes due to
+  // keystroke, tap gesture, and caret placement. Ignore selection changes while
+  // the mouse is down, as we generally defer handling that until mouse release.
+  if (state_changes.selection_differs && !is_mouse_pressed_ &&
+      UnapplySteadyStateElisions()) {
     something_changed = true;
     state_changes.text_differs = true;
   }
@@ -702,7 +701,16 @@ bool OmniboxViewViews::OnMousePressed(const ui::MouseEvent& event) {
     // invalidated this saved selection is still OK.
     saved_selection_for_focus_change_ = gfx::Range::InvalidRange();
   }
-  return views::Textfield::OnMousePressed(event);
+
+  bool handled = views::Textfield::OnMousePressed(event);
+
+  // This ensures that when the user makes a double-click partial select, we
+  // perform the unelision at the same time as we make the partial selection,
+  // which is on mousedown.
+  if (!select_all_on_mouse_release_ && UnapplySteadyStateElisions())
+    TextChanged();
+
+  return handled;
 }
 
 bool OmniboxViewViews::OnMouseDragged(const ui::MouseEvent& event) {
@@ -730,6 +738,8 @@ void OmniboxViewViews::OnMouseReleased(const ui::MouseEvent& event) {
   }
   select_all_on_mouse_release_ = false;
 
+  // Make an unelision check on mouse release. This handles the drag selection
+  // case, in which we defer uneliding until mouse release.
   is_mouse_pressed_ = false;
   if (UnapplySteadyStateElisions())
     TextChanged();