Disable rasterizer discard during CopyTextureCHROMIUM.

Otherwise if the user sets this state, the copy command would be
silently skipped.

It did not seem practical to implement the large-scale refactor
suggested in the bug report to avoid setting the texture's level as
cleared.

Integrated modified version of the test case from the bug report.

Co-authored with jetski-cli.

Fixed: 500138014
Change-Id: I24c8ddbcfb19e4fadec85bec9f407bde091db8b5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7798563
Commit-Queue: Vasiliy Telezhnikov <vasilyt@chromium.org>
Auto-Submit: Kenneth Russell <kbr@chromium.org>
Reviewed-by: Vasiliy Telezhnikov <vasilyt@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1621709}

gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc

diff --git a/gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc b/gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc
index a73cca8..f06fba6a 100644
--- a/gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc
+++ b/gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc
@@ -1424,6 +1424,9 @@
     glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
     glDepthMask(GL_FALSE);
     glDisable(GL_BLEND);
+    if (decoder->GetFeatureInfo()->IsWebGL2OrES3OrHigherContext()) {
+      glDisable(GL_RASTERIZER_DISCARD);
+    }
 
     bool need_scissor =
         xoffset || yoffset || width != dest_width || height != dest_height;

gpu/command_buffer/tests/gl_copy_texture_CHROMIUM_unittest.cc

diff --git a/gpu/command_buffer/tests/gl_copy_texture_CHROMIUM_unittest.cc b/gpu/command_buffer/tests/gl_copy_texture_CHROMIUM_unittest.cc
index 0e05828..28135403 100644
--- a/gpu/command_buffer/tests/gl_copy_texture_CHROMIUM_unittest.cc
+++ b/gpu/command_buffer/tests/gl_copy_texture_CHROMIUM_unittest.cc
@@ -1850,4 +1850,102 @@
   glDeleteFramebuffers(1, &framebuffer_id_);
 }
 
+TEST_P(GLCopyTextureCHROMIUMES3Test, RasterizerDiscardDoesNotInterfere) {
+#if !BUILDFLAG(ENABLE_VALIDATING_COMMAND_DECODER)
+  GTEST_SKIP() << "Test only reproduces with validating decoder";
+#else
+  if (gl_.gpu_preferences().use_passthrough_cmd_decoder) {
+    GTEST_SKIP() << "Skipping test because it's run with the passthrough "
+                    "command decoder";
+  }
+
+  if (!gl_.IsInitialized()) {
+    GTEST_SKIP() << "ES3 context unavailable";
+  }
+
+  constexpr GLsizei kW = 64, kH = 64;
+
+  // --- Step 1: prime VRAM with a recognisable pattern, then free it. ---
+  {
+    GLuint prime;
+    glGenTextures(1, &prime);
+    glBindTexture(GL_TEXTURE_2D, prime);
+    std::vector<uint8_t> pat(kW * kH * 4, 0xCA);
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, kW, kH, 0, GL_RGBA,
+                 GL_UNSIGNED_BYTE, pat.data());
+    glFinish();
+    glDeleteTextures(1, &prime);
+  }
+
+  // --- Step 2: dest texture, allocated WITHOUT data → uninitialized VRAM. ---
+  GLuint dest;
+  glGenTextures(1, &dest);
+  glBindTexture(GL_TEXTURE_2D, dest);
+  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, kW, kH, 0, GL_RGBA, GL_UNSIGNED_BYTE,
+               nullptr);
+
+  // --- Step 3: trivial source texture (contents irrelevant). ---
+  GLuint src;
+  glGenTextures(1, &src);
+  glBindTexture(GL_TEXTURE_2D, src);
+  std::vector<uint8_t> green(kW * kH * 4, 0);
+  for (size_t i = 0; i < green.size(); i += 4) {
+    green[i + 1] = 0xFF;  // G
+    green[i + 3] = 0xFF;  // A
+  }
+  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, kW, kH, 0, GL_RGBA, GL_UNSIGNED_BYTE,
+               green.data());
+
+  // --- Step 4: enable RASTERIZER_DISCARD on the command-buffer context. ---
+  glEnable(GL_RASTERIZER_DISCARD);
+  ASSERT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+
+  // --- Step 5: issue the copy. flip_y=GL_TRUE forces a draw-based path ---
+  CopyType copy_type = GetParam();
+  if (copy_type == TexImage) {
+    glCopyTextureCHROMIUM(src, 0, GL_TEXTURE_2D, dest, 0, GL_RGBA8,
+                          GL_UNSIGNED_BYTE, GL_TRUE, GL_FALSE, GL_FALSE);
+  } else {
+    glCopySubTextureCHROMIUM(src, 0, GL_TEXTURE_2D, dest, 0, 0, 0, 0, 0, kW, kH,
+                             GL_TRUE, GL_FALSE, GL_FALSE);
+  }
+  ASSERT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+
+  glDisable(GL_RASTERIZER_DISCARD);
+
+  // --- Step 6: read back. ---
+  GLuint fbo;
+  glGenFramebuffers(1, &fbo);
+  glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+  glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
+                         dest, 0);
+  ASSERT_EQ(static_cast<GLenum>(GL_FRAMEBUFFER_COMPLETE),
+            glCheckFramebufferStatus(GL_FRAMEBUFFER));
+
+  std::vector<uint8_t> pixels(kW * kH * 4, 0);
+  glReadPixels(0, 0, kW, kH, GL_RGBA, GL_UNSIGNED_BYTE, pixels.data());
+  ASSERT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+
+  // --- Step 7: prove the leak is gone (copy succeeded). ---
+  size_t nonzero = 0, green_px = 0;
+  for (size_t i = 0; i < pixels.size(); i += 4) {
+    if (pixels[i] || pixels[i + 1] || pixels[i + 2] || pixels[i + 3]) {
+      ++nonzero;
+    }
+    if (pixels[i] == 0x00 && pixels[i + 1] == 0xFF && pixels[i + 2] == 0x00 &&
+        pixels[i + 3] == 0xFF) {
+      ++green_px;
+    }
+  }
+
+  // Expect all pixels to be green.
+  EXPECT_EQ(green_px, static_cast<size_t>(kW * kH));
+  EXPECT_GT(nonzero, 0u);
+
+  glDeleteFramebuffers(1, &fbo);
+  glDeleteTextures(1, &src);
+  glDeleteTextures(1, &dest);
+#endif  // !BUILDFLAG(ENABLE_VALIDATING_COMMAND_DECODER)
+}
+
 }  // namespace gpu