Clear the software mirroring display list when adding it to the updat…

…ed list.

BUG=601505
TEST=DisplayManagerTest.SoftwareMirroringAndRotate
R=stevenjb@chromium.org

Review URL: https://codereview.chromium.org/1870733004

Cr-Commit-Position: refs/heads/master@{#385871}

ash/display/display_manager.cc

@@ -1221,8 +1221,10 @@ gfx::Display* DisplayManager::FindDisplayForId(int64_t id) {
 
 void DisplayManager::AddMirrorDisplayInfoIfAny(
     std::vector<DisplayInfo>* display_info_list) {
-  if (software_mirroring_enabled() && IsInMirrorMode())
+  if (software_mirroring_enabled() && IsInMirrorMode()) {
     display_info_list->push_back(GetDisplayInfo(mirroring_display_id_));
+    software_mirroring_display_list_.clear();
+  }
 }
 
 void DisplayManager::InsertAndUpdateDisplayInfo(const DisplayInfo& new_info) {

ash/display/display_manager_unittest.cc

@@ -1484,6 +1484,21 @@ TEST_F(DisplayManagerTest, SoftwareMirroring) {
   gfx::Screen::GetScreen()->RemoveObserver(&display_observer);
 }
 
+TEST_F(DisplayManagerTest, RotateInSoftwareMirroring) {
+  if (!SupportsMultipleDisplays())
+    return;
+
+  DisplayManager* display_manager = Shell::GetInstance()->display_manager();
+  UpdateDisplay("600x400,500x300");
+  display_manager->SetMirrorMode(true);
+
+  EXPECT_EQ(1U, display_manager->GetNumDisplays());
+  int64_t primary_id = gfx::Screen::GetScreen()->GetPrimaryDisplay().id();
+  display_manager->SetDisplayRotation(primary_id, gfx::Display::ROTATE_180,
+                                      gfx::Display::ROTATION_SOURCE_ACTIVE);
+  display_manager->SetMirrorMode(false);
+}
+
 TEST_F(DisplayManagerTest, SingleDisplayToSoftwareMirroring) {
   if (!SupportsMultipleDisplays())
     return;