Force buffer re-allocation when the backing display changes

ui/ozone/platform/drm/gpu/drm_surface_unittest.cc

Index: ui/ozone/platform/drm/gpu/drm_surface_unittest.cc
diff --git a/ui/ozone/platform/drm/gpu/drm_surface_unittest.cc b/ui/ozone/platform/drm/gpu/drm_surface_unittest.cc
index 4498f1fc28afe80865f7be1892310efff307cb23..13774b2659c2d437c2b8582d7435b9d7c2a665e3 100644
--- a/ui/ozone/platform/drm/gpu/drm_surface_unittest.cc
+++ b/ui/ozone/platform/drm/gpu/drm_surface_unittest.cc
@@ -73,6 +73,10 @@ void DrmSurfaceTest::SetUp() {
       new ui::DrmSurface(screen_manager_->GetWindow(kDefaultWidgetHandle)));
   surface_->ResizeCanvas(
       gfx::Size(kDefaultMode.hdisplay, kDefaultMode.vdisplay));
+
+  // The window has been remapped to a controller. The first swap will cause the
+  // SWAP_NAK_RECREATE_BUFFERS without actually using the buffers.
+  surface_->PresentCanvas(gfx::Rect());
 }
 
 void DrmSurfaceTest::TearDown() {
@@ -88,10 +92,10 @@ TEST_F(DrmSurfaceTest, CheckFBIDOnSwap) {
   surface_->PresentCanvas(gfx::Rect());
   drm_->RunCallbacks();
   // Framebuffer ID 1 is allocated in SetUp for the buffer used to modeset.
-  EXPECT_EQ(3u, drm_->current_framebuffer());
+  EXPECT_EQ(2u, drm_->current_framebuffer());
   surface_->PresentCanvas(gfx::Rect());
   drm_->RunCallbacks();
-  EXPECT_EQ(2u, drm_->current_framebuffer());
+  EXPECT_EQ(3u, drm_->current_framebuffer());
 }
 
 TEST_F(DrmSurfaceTest, CheckSurfaceContents) {
@@ -115,12 +119,12 @@ TEST_F(DrmSurfaceTest, CheckSurfaceContents) {
     framebuffers.push_back(buffer);
   }
 
-  // Buffer 0 is the modesetting buffer, buffer 1 is the frontbuffer and buffer
-  // 2 is the backbuffer.
+  // Buffer 0 is the modesetting buffer, buffer 2 is the frontbuffer and buffer
+  // 1 is the backbuffer.
   EXPECT_EQ(3u, framebuffers.size());
 
-  image.setInfo(framebuffers[2]->getCanvas()->imageInfo());
-  EXPECT_TRUE(framebuffers[2]->getCanvas()->readPixels(&image, 0, 0));
+  image.setInfo(framebuffers[1]->getCanvas()->imageInfo());
+  EXPECT_TRUE(framebuffers[1]->getCanvas()->readPixels(&image, 0, 0));
 
   EXPECT_EQ(kDefaultMode.hdisplay, image.width());
   EXPECT_EQ(kDefaultMode.vdisplay, image.height());
@@ -167,12 +171,12 @@ TEST_F(DrmSurfaceTest, CheckSurfaceContentsAfter2QueuedPresents) {
     framebuffers.push_back(buffer);
   }
 
-  // Buffer 0 is the modesetting buffer, buffer 1 is the backbuffer and buffer
-  // 2 is the frontbuffer.
+  // Buffer 0 is the modesetting buffer, buffer 2 is the backbuffer and buffer
+  // 1 is the frontbuffer.
   EXPECT_EQ(3u, framebuffers.size());
 
-  image.setInfo(framebuffers[1]->getCanvas()->imageInfo());
-  EXPECT_TRUE(framebuffers[1]->getCanvas()->readPixels(&image, 0, 0));
+  image.setInfo(framebuffers[2]->getCanvas()->imageInfo());
+  EXPECT_TRUE(framebuffers[2]->getCanvas()->readPixels(&image, 0, 0));
 
   EXPECT_EQ(kDefaultMode.hdisplay, image.width());
   EXPECT_EQ(kDefaultMode.vdisplay, image.height());