Bind framebuffer to fbo_ object before readPixels, rather than multisample_fbo_

third_party/WebKit/Source/platform/graphics/gpu/DrawingBufferSoftwareRenderingTest.cpp

Index: third_party/WebKit/Source/platform/graphics/gpu/DrawingBufferSoftwareRenderingTest.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/gpu/DrawingBufferSoftwareRenderingTest.cpp b/third_party/WebKit/Source/platform/graphics/gpu/DrawingBufferSoftwareRenderingTest.cpp
index edcd8be52c9820136312cdf408d0288e0b8e36af..ee906e8e9c648069c7dbb82efe9a8903848e22b9 100644
--- a/third_party/WebKit/Source/platform/graphics/gpu/DrawingBufferSoftwareRenderingTest.cpp
+++ b/third_party/WebKit/Source/platform/graphics/gpu/DrawingBufferSoftwareRenderingTest.cpp
@@ -49,21 +49,23 @@ class DrawingBufferSoftwareRenderingTest : public Test {
     IntSize initial_size(kInitialWidth, kInitialHeight);
     std::unique_ptr<GLES2InterfaceForTests> gl =
         WTF::WrapUnique(new GLES2InterfaceForTests);
+    gl_ = gl.get();

[Ken Russell (switch to Gerrit), 2017/06/01 21:37:43]

Agree with Mo's point that caching this weak pointer could lead to fragile code.
I do see however that several of the other tests are doing it this way.

Could you instead add to DrawingBufferForTests:

  GLES2InterfaceForTests* ContextGLForTests() {
    return static_cast<GLES2InterfaceForTests*>(drawing_buffer_->ContextGL());
  }

This assumes that all DrawingBufferForTests instances are set up with a
GLES2InterfaceForTests. I think that's a safe assumption. Then call this method
where the GLES2InterfaceForTests is needed. It would be nice to clean up the
other tests which are doing this caching as well.

[xinghua.cao, 2017/06/02 16:06:28]

Hi, ken, Do you mean that add ContextGLForTests() function in
DrawingBufferForTests class? But DrawingBufferForTests does not have the
drawing_buffer_ member, I think here only need to call "ContextGL()" directly,
is that right?

[Ken Russell (switch to Gerrit), 2017/06/02 21:54:14]

Ah I misunderstood. Anyway, you fixed this in your most recent patch set --
thanks.

     std::unique_ptr<WebGraphicsContext3DProviderSoftwareRenderingForTests>
         provider = WTF::WrapUnique(
             new WebGraphicsContext3DProviderSoftwareRenderingForTests(
                 std::move(gl)));
     drawing_buffer_ = DrawingBufferForTests::Create(
-        std::move(provider), nullptr, initial_size, DrawingBuffer::kPreserve,
+        std::move(provider), gl_, initial_size, DrawingBuffer::kPreserve,
         kDisableMultisampling);
     CHECK(drawing_buffer_);
   }
 
   RefPtr<DrawingBufferForTests> drawing_buffer_;
+  GLES2InterfaceForTests* gl_;
   bool is_software_rendering_ = false;
 };
 
-TEST_F(DrawingBufferSoftwareRenderingTest, bitmapRecycling) {
+TEST_F(DrawingBufferSoftwareRenderingTest, BitmapRecycling) {
   cc::TextureMailbox texture_mailbox;
   std::unique_ptr<cc::SingleReleaseCallback> release_callback1;
   std::unique_ptr<cc::SingleReleaseCallback> release_callback2;
@@ -101,5 +103,28 @@ TEST_F(DrawingBufferSoftwareRenderingTest, bitmapRecycling) {
   drawing_buffer_->BeginDestruction();
 }
 
+TEST_F(DrawingBufferSoftwareRenderingTest, FramebufferBinding) {
+  cc::TextureMailbox texture_mailbox;
+  std::unique_ptr<cc::SingleReleaseCallback> release_callback;
+  IntSize initial_size(kInitialWidth, kInitialHeight);
+  GLint drawBinding = 0, readBinding = 0;
+
+  GLuint draw_framebuffer_binding = 0xbeef3;
+  GLuint read_framebuffer_binding = 0xbeef4;
+  gl_->BindFramebuffer(GL_DRAW_FRAMEBUFFER, draw_framebuffer_binding);
+  gl_->BindFramebuffer(GL_READ_FRAMEBUFFER, read_framebuffer_binding);
+  gl_->SaveState();
+  drawing_buffer_->Resize(initial_size);
+  drawing_buffer_->MarkContentsChanged();
+  drawing_buffer_->PrepareTextureMailbox(&texture_mailbox, &release_callback);
+  gl_->GetIntegerv(GL_DRAW_FRAMEBUFFER_BINDING, &drawBinding);
+  gl_->GetIntegerv(GL_READ_FRAMEBUFFER_BINDING, &readBinding);
+  EXPECT_EQ(static_cast<GLint>(draw_framebuffer_binding), drawBinding);
+  EXPECT_EQ(static_cast<GLint>(read_framebuffer_binding), readBinding);
+  release_callback->Run(gpu::SyncToken(), false /* lostResource */);
+
+  drawing_buffer_->BeginDestruction();
+}
+
 }  // unnamed namespace
 }  // blink