Allow creating opaque swapchains in DirectCompositionSurfaceWin

gpu/ipc/service/direct_composition_surface_win_unittest.cc

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "gpu/ipc/service/direct_composition_surface_win.h"
 #include "base/memory/weak_ptr.h"
 #include "base/run_loop.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "skia/ext/platform_canvas.h"
@@ skipping 194 matching lines @@
   // Surface switched to use IDXGISwapChain, so must draw to entire
   // surface.
   EXPECT_FALSE(surface->SetDrawRectangle(gfx::Rect(0, 0, 50, 50)));
   EXPECT_TRUE(surface->SetDrawRectangle(gfx::Rect(0, 0, 100, 100)));
   EXPECT_TRUE(surface->swap_chain());
 
   context = nullptr;
   DestroySurface(std::move(surface));
 }
 
+// Ensure that the swapchain's alpha is correct.
+TEST(DirectCompositionSurfaceTest, SwitchAlpha) {
+  if (!CheckIfDCSupported())
+    return;
+
+  TestImageTransportSurfaceDelegate delegate;
+
+  scoped_refptr<DirectCompositionSurfaceWin> surface(
+      new DirectCompositionSurfaceWin(delegate.AsWeakPtr(),
+                                      ui::GetHiddenWindow()));
+  EXPECT_TRUE(surface->Initialize());
+
+  scoped_refptr<gl::GLContext> context =
+      gl::init::CreateGLContext(nullptr, surface.get(), gl::GLContextAttribs());
+  EXPECT_TRUE(surface->Resize(gfx::Size(100, 100), 1.0, true));
+  EXPECT_FALSE(surface->swap_chain());
+
+  EXPECT_TRUE(surface->SetDrawRectangle(gfx::Rect(0, 0, 100, 100)));
+  base::win::ScopedComPtr<IDXGISwapChain1> swap_chain = surface->swap_chain();
+  ASSERT_TRUE(swap_chain);

[sunnyps, 2017/03/28 23:33:29]

nit: Why ASSERT instead of EXPECT here and below?

[jbauman, 2017/03/28 23:40:58]

If it's null then swap_chain->GetDesc1 will crash, so we might as well give up
early.

+  DXGI_SWAP_CHAIN_DESC1 desc;
+  swap_chain->GetDesc1(&desc);
+  EXPECT_EQ(DXGI_ALPHA_MODE_PREMULTIPLIED, desc.AlphaMode);
+
+  // Resize to the same parameters should have no effect.
+  EXPECT_TRUE(surface->Resize(gfx::Size(100, 100), 1.0, true));
+  EXPECT_TRUE(surface->swap_chain());
+
+  EXPECT_TRUE(surface->Resize(gfx::Size(100, 100), 1.0, false));
+  EXPECT_FALSE(surface->swap_chain());
+
+  EXPECT_TRUE(surface->SetDrawRectangle(gfx::Rect(0, 0, 100, 100)));
+
+  swap_chain = surface->swap_chain();
+  ASSERT_TRUE(swap_chain);
+  swap_chain->GetDesc1(&desc);
+  EXPECT_EQ(DXGI_ALPHA_MODE_IGNORE, desc.AlphaMode);
+
+  context = nullptr;
+  DestroySurface(std::move(surface));
+}
+
 SkBitmap ReadBackWindow(HWND window, const gfx::Rect& snapshot_bounds) {
   std::unique_ptr<SkCanvas> canvas = skia::CreatePlatformCanvas(
       snapshot_bounds.right(), snapshot_bounds.bottom(), false);
   HDC mem_hdc = skia::GetNativeDrawingContext(canvas.get());
 
   // Grab a copy of the window. Use PrintWindow because it works even when the
   // window's partially occluded. The PW_RENDERFULLCONTENT flag is undocumented,
   // but works starting in Windows 8.1. It allows for capturing the contents of
   // the window that are drawn using DirectComposition.
   UINT flags = PW_CLIENTONLY | PW_RENDERFULLCONTENT;
@@ skipping 142 matching lines @@
   EXPECT_TRUE(AreColorsSimilar(expected_color, actual_color))
       << std::hex << "Expected " << expected_color << " Actual "
       << actual_color;
 
   context = nullptr;
   DestroySurface(std::move(surface_));
 }
 
 }  // namespace
 }  // namespace gpu