Fix software mirror mode on Ozone part 2/2

ash/touch/touch_transformer_controller.cc

Index: ash/touch/touch_transformer_controller.cc
diff --git a/ash/touch/touch_transformer_controller.cc b/ash/touch/touch_transformer_controller.cc
index d88416e6feb9146f2729ed1a597df3d2ece1993c..e5e03bde233be3a9b734c679d55a293b899f0af9 100644
--- a/ash/touch/touch_transformer_controller.cc
+++ b/ash/touch/touch_transformer_controller.cc
@@ -178,11 +178,14 @@ void TouchTransformerController::UpdateTouchTransformer() const {
       Shell::GetInstance()->display_configurator()->framebuffer_size();
 
   if (display_state == ui::MULTIPLE_DISPLAY_STATE_DUAL_MIRROR) {
-    // In mirror mode, both displays share the same root window so
-    // both display ids are associated with the root window.
-    aura::Window* root = display_controller->GetPrimaryRootWindow();
-    RootWindowController::ForWindow(root)->ash_host()->UpdateDisplayID(
-        display1_id, display2_id);
+    // In mirror mode, there is just one WindowTreeHost and two displays. Make
+    // the WindowTreeHost accept touch events from both displays.
+    int64 primary_display_id = display_controller->GetPrimaryDisplayId();
+    device_manager->SetTargetDisplayForTouchDevice(display1.touch_device_id(),
+                                                   primary_display_id);
+    device_manager->SetTargetDisplayForTouchDevice(display2.touch_device_id(),
+                                                   primary_display_id);
+
     device_manager->UpdateTouchInfoForDisplay(
         display1_id, display1.touch_device_id(),
         GetTouchTransform(display1, display1,
@@ -197,38 +200,38 @@ void TouchTransformerController::UpdateTouchTransformer() const {
   }
 
   if (display_state == ui::MULTIPLE_DISPLAY_STATE_DUAL_EXTENDED) {
-    // In extended but software mirroring mode, ther is only one X root window
-    // that associates with both displays.
+    // In extended but software mirroring mode, there is a WindowTreeHost for
+    // each display, but all touches are forwarded to the primary root window's
+    // WindowTreeHost.
     if (GetDisplayManager()->software_mirroring_enabled())  {
-      aura::Window* root = display_controller->GetPrimaryRootWindow();
-      RootWindowController::ForWindow(root)->ash_host()->UpdateDisplayID(
-          display1_id, display2_id);
-      DisplayInfo source_display =
+      DisplayInfo target_display =
           display_controller->GetPrimaryDisplayId() == display1_id ? display1
                                                                    : display2;
+      device_manager->SetTargetDisplayForTouchDevice(display1.touch_device_id(),
+                                                     target_display.id());
+      device_manager->SetTargetDisplayForTouchDevice(display2.touch_device_id(),
+                                                     target_display.id());
+
       // Mapping from framebuffer size to the source display's native
       // resolution.
       device_manager->UpdateTouchInfoForDisplay(
           display1_id, display1.touch_device_id(),
-          GetTouchTransform(source_display, display1,
+          GetTouchTransform(target_display, display1,
                             FindTouchscreenById(display1.touch_device_id()),
                             fb_size));
       device_manager->UpdateTouchInfoForDisplay(
           display2_id, display2.touch_device_id(),
-          GetTouchTransform(source_display, display2,
+          GetTouchTransform(target_display, display2,
                             FindTouchscreenById(display2.touch_device_id()),
                             fb_size));
     } else {
-      // In actual extended mode, each display is associated with one root
-      // window.
-      aura::Window* root1 =
-          display_controller->GetRootWindowForDisplayId(display1_id);
-      aura::Window* root2 =
-          display_controller->GetRootWindowForDisplayId(display2_id);
-      RootWindowController::ForWindow(root1)->ash_host()->UpdateDisplayID(
-          display1_id, gfx::Display::kInvalidDisplayID);
-      RootWindowController::ForWindow(root2)->ash_host()->UpdateDisplayID(
-          display2_id, gfx::Display::kInvalidDisplayID);
+      // In actual extended mode, each display is associated with one
+      // WindowTreeHost.
+      device_manager->SetTargetDisplayForTouchDevice(display1.touch_device_id(),
+                                                     display1.id());
+      device_manager->SetTargetDisplayForTouchDevice(display2.touch_device_id(),
+                                                     display2.id());
+
       // Mapping from framebuffer size to each display's native resolution.
       device_manager->UpdateTouchInfoForDisplay(
           display1_id, display1.touch_device_id(),
@@ -244,11 +247,9 @@ void TouchTransformerController::UpdateTouchTransformer() const {
     return;
   }
 
-  // Single display mode. The root window has one associated display id.
-  aura::Window* root =
-      display_controller->GetRootWindowForDisplayId(single_display.id());
-  RootWindowController::ForWindow(root)->ash_host()->UpdateDisplayID(
-      single_display.id(), gfx::Display::kInvalidDisplayID);
+  // Single display mode. The WindowTreeHost has one associated display id.
+  device_manager->SetTargetDisplayForTouchDevice(
+      single_display.touch_device_id(), single_display.id());
   device_manager->UpdateTouchInfoForDisplay(
       single_display_id, single_display.touch_device_id(),
       GetTouchTransform(single_display, single_display,