Use IDCompositionSurface to implement DirectCompositionSurfaceWin.

cc/output/gl_renderer_unittest.cc

Index: cc/output/gl_renderer_unittest.cc
diff --git a/cc/output/gl_renderer_unittest.cc b/cc/output/gl_renderer_unittest.cc
index 0cf7d508ae37abe27e2b7368ccdfb327a15a20d8..a06b1bf0c0fb5b8d49a8bfcf1cd84cb82f3568e2 100644
--- a/cc/output/gl_renderer_unittest.cc
+++ b/cc/output/gl_renderer_unittest.cc
@@ -1495,6 +1495,7 @@ class MockOutputSurface : public OutputSurface {
                     bool has_alpha,
                     bool use_stencil));
   MOCK_METHOD0(BindFramebuffer, void());
+  MOCK_METHOD1(SetDrawRectangle, void(const gfx::Rect&));
   MOCK_METHOD0(GetFramebufferCopyTextureFormat, GLenum());
   MOCK_METHOD1(SwapBuffers_, void(OutputSurfaceFrame& frame));  // NOLINT
   void SwapBuffers(OutputSurfaceFrame frame) override { SwapBuffers_(frame); }
@@ -1872,12 +1873,14 @@ class PartialSwapMockGLES2Interface : public TestGLES2Interface {
 
 class GLRendererPartialSwapTest : public GLRendererTest {
  protected:
-  void RunTest(bool partial_swap) {
+  void RunTest(bool partial_swap, bool set_draw_rectangle) {
     auto gl_owned = base::MakeUnique<PartialSwapMockGLES2Interface>();
     auto* gl = gl_owned.get();
 
     auto provider = TestContextProvider::Create(std::move(gl_owned));
     provider->BindToCurrentThread();
+    provider->TestContext3d()->set_support_set_draw_rectangle(
+        set_draw_rectangle);
 
     FakeOutputSurfaceClient output_surface_client;
     std::unique_ptr<FakeOutputSurface> output_surface(
@@ -1917,12 +1920,18 @@ class GLRendererPartialSwapTest : public GLRendererTest {
       // Partial frame, we should use a scissor to swap only that part when
       // partial swap is enabled.
       root_pass->damage_rect = gfx::Rect(2, 2, 3, 3);
+      gfx::Rect output_rectangle =
+          partial_swap ? root_pass->damage_rect : gfx::Rect(viewport_size);
 
-      if (partial_swap) {
+      if (partial_swap || set_draw_rectangle) {
         EXPECT_CALL(*gl, Enable(GL_SCISSOR_TEST)).InSequence(seq);
         // The scissor is flipped, so subtract the y coord and height from the
         // bottom of the GL viewport.
-        EXPECT_CALL(*gl, Scissor(2, viewport_size.height() - 3 - 2, 3, 3))
+        EXPECT_CALL(
+            *gl, Scissor(output_rectangle.x(),
+                         viewport_size.height() - output_rectangle.y() -
+                             output_rectangle.height(),
+                         output_rectangle.width(), output_rectangle.height()))
             .InSequence(seq);
       }
 
@@ -1935,16 +1944,27 @@ class GLRendererPartialSwapTest : public GLRendererTest {
       renderer.DecideRenderPassAllocationsForFrame(
           render_passes_in_draw_order_);
       DrawFrame(&renderer, viewport_size);
+      if (set_draw_rectangle) {
+        EXPECT_EQ(output_rectangle, output_surface->last_set_draw_rectangle());

[danakj, 2017/02/23 23:38:51]

FWIW you could mock and EXPECT the method instead of adding state+getters on
FakeOutputSurface. up to u

+      }
     }
   }
 };
 
 TEST_F(GLRendererPartialSwapTest, PartialSwap) {
-  RunTest(true);
+  RunTest(true, false);
 }
 
 TEST_F(GLRendererPartialSwapTest, NoPartialSwap) {
-  RunTest(false);
+  RunTest(false, false);
+}
+
+TEST_F(GLRendererPartialSwapTest, SetDrawRectangle) {

[danakj, 2017/02/23 23:38:51]

nit: maybe name the two test variants a bit more explicitly?
SetDrawRectangle_PartialSwap and SetDrawRectangle_NoPartialSwap?

+  RunTest(true, true);
+}
+
+TEST_F(GLRendererPartialSwapTest, SetDrawRectangleNoPartialSwap) {
+  RunTest(false, true);
 }
 
 class GLRendererWithMockContextTest : public ::testing::Test {