Automatically set the overscan insets if the output has the flag and no preference is set.

ash/display/display_manager_unittest.cc

Index: ash/display/display_manager_unittest.cc
diff --git a/ash/display/display_manager_unittest.cc b/ash/display/display_manager_unittest.cc
index 33645a2431d2e0906c8f9177b3230c71eda9ed94..09b4ab05a33f0ce76371c31e30a691b7a53b355a 100644
--- a/ash/display/display_manager_unittest.cc
+++ b/ash/display/display_manager_unittest.cc
@@ -514,5 +514,33 @@ TEST_F(DisplayManagerTest, NativeDisplaysChangedAfterPrimaryChange) {
   EXPECT_EQ("0,0 100x100", FindDisplayForId(10).bounds().ToString());
 }
 
+TEST_F(DisplayManagerTest, AutomaticOverscanInsets) {
+  UpdateDisplay("200x200,400x400");
+
+  std::vector<gfx::Display> displays;
+  displays.push_back(*display_manager()->GetDisplayAt(0));
+  displays.push_back(*display_manager()->GetDisplayAt(1));
+  int64 id = displays[1].id();
+  display_manager()->SetHasOverscanFlagForTest(id, true);
+
+  display_manager()->OnNativeDisplaysChanged(displays);
+  // It has overscan insets, although SetOverscanInsets() isn't called.
+  EXPECT_EQ("11,211 380x380",
+            display_manager()->GetDisplayAt(1)->bounds_in_pixel().ToString());
+
+  // If custom overscan insets is specified, the specified value is used.
+  display_manager()->SetOverscanInsets(id, gfx::Insets(5, 6, 7, 8));
+  display_manager()->OnNativeDisplaysChanged(displays);
+  EXPECT_EQ("7,206 386x388",
+            display_manager()->GetDisplayAt(1)->bounds_in_pixel().ToString());
+
+  // Do not overscan even though it has 'has_overscan' flag, if the custom
+  // insets is empty.
+  display_manager()->SetOverscanInsets(id, gfx::Insets());
+  display_manager()->OnNativeDisplaysChanged(displays);
+  EXPECT_EQ("1,201 400x400",
+            display_manager()->GetDisplayAt(1)->bounds_in_pixel().ToString());
+}
+
 }  // namespace internal
 }  // namespace ash