Notify primary display reassignment

ash/display/display_controller_unittest.cc

Index: ash/display/display_controller_unittest.cc
diff --git a/ash/display/display_controller_unittest.cc b/ash/display/display_controller_unittest.cc
index e9dd69f67e61ea3ddb1454bbacb6dc184f8101a9..5868e03f3c04bd8933039bd9dd3605e502a7d569 100644
--- a/ash/display/display_controller_unittest.cc
+++ b/ash/display/display_controller_unittest.cc
@@ -581,9 +581,10 @@ TEST_F(DisplayControllerTest, MirrorToDockedWithFullscreen) {
   display_manager->OnNativeDisplaysChanged(display_info_list);
   EXPECT_EQ(1U, display_manager->GetNumDisplays());
   EXPECT_EQ(1U, display_manager->num_connected_displays());
-  EXPECT_EQ(0, observer.GetChangedDisplayIdAndReset());
-  EXPECT_EQ(0, observer.GetBoundsChangedCountAndReset());
-  EXPECT_EQ(0, observer.GetWorkareaChangedCountAndReset());
+  // Observers are called due to primary change.
+  EXPECT_EQ(2, observer.GetChangedDisplayIdAndReset());
+  EXPECT_EQ(1, observer.GetBoundsChangedCountAndReset());
+  EXPECT_EQ(1, observer.GetWorkareaChangedCountAndReset());

[Jun Mukai, 2014/11/20 00:58:38]

better to modify observer to recognize the primary change and add an expectation
that primary change arrives?

[oshima, 2014/11/20 01:12:20]

Done.

   EXPECT_EQ(1, observer.CountAndReset());
   EXPECT_EQ(0, observer.GetFocusChangedCountAndReset());
   EXPECT_EQ(0, observer.GetActivationChangedCountAndReset());