From ec99c09baf05ce19f64b215482faf03296ed3afe Mon Sep 17 00:00:00 2001
From: Dan Field <dnfield@google.com>
Date: Thu, 7 Apr 2022 09:22:08 -0700
Subject: [PATCH] Soft revert of 3a0d0b6e36deebc6d477daee9a3cc4dbd09a7900
 (flutter/engine#32465)

---
 engine/src/flutter/shell/common/context_options.cc          | 6 ++++++
 .../src/flutter/shell/common/context_options_unittests.cc   | 4 ++--
 engine/src/flutter/shell/gpu/gpu_surface_gl.cc              | 2 +-
 .../flutter/shell/platform/android/android_context_gl.cc    | 2 +-
 engine/src/flutter/shell/platform/embedder/embedder.cc      | 2 +-
 5 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/engine/src/flutter/shell/common/context_options.cc b/engine/src/flutter/shell/common/context_options.cc
index 073c9fcb7fb..3ae89865de5 100644
--- a/engine/src/flutter/shell/common/context_options.cc
+++ b/engine/src/flutter/shell/common/context_options.cc
@@ -19,6 +19,12 @@ GrContextOptions MakeDefaultContextOptions(ContextType type,
   options.fPersistentCache = PersistentCache::GetCacheForProcess();
 
   if (api.has_value() && api.value() == GrBackendApi::kOpenGL) {
+    // Using stencil buffers has caused memory and performance regressions.
+    // See b/226484927 for internal customer regressions doc.
+    // Before enabling, we need to show a motivating case for where it will
+    // improve performance on OpenGL backend.
+    options.fAvoidStencilBuffers = true;
+
     // To get video playback on the widest range of devices, we limit Skia to
     // ES2 shading language when the ES3 external image extension is missing.
     options.fPreferExternalImagesOverES3 = true;
diff --git a/engine/src/flutter/shell/common/context_options_unittests.cc b/engine/src/flutter/shell/common/context_options_unittests.cc
index 7e576eeeff4..e49f8e28949 100644
--- a/engine/src/flutter/shell/common/context_options_unittests.cc
+++ b/engine/src/flutter/shell/common/context_options_unittests.cc
@@ -9,10 +9,10 @@
 namespace flutter {
 namespace testing {
 
-TEST(ContextOptionsTest, OpenGLAllowsStencilBuffers) {
+TEST(ContextOptionsTest, OpenGLDisablesStencilBuffers) {
   auto options = MakeDefaultContextOptions(flutter::ContextType::kRender,
                                            GrBackendApi::kOpenGL);
-  EXPECT_FALSE(options.fAvoidStencilBuffers);
+  EXPECT_TRUE(options.fAvoidStencilBuffers);
 }
 
 }  // namespace testing
diff --git a/engine/src/flutter/shell/gpu/gpu_surface_gl.cc b/engine/src/flutter/shell/gpu/gpu_surface_gl.cc
index 0ce3fda026c..068ae70519a 100644
--- a/engine/src/flutter/shell/gpu/gpu_surface_gl.cc
+++ b/engine/src/flutter/shell/gpu/gpu_surface_gl.cc
@@ -139,7 +139,7 @@ static sk_sp<SkSurface> WrapOnscreenSurface(GrDirectContext* context,
   GrBackendRenderTarget render_target(size.width(),     // width
                                       size.height(),    // height
                                       0,                // sample count
-                                      8,                // stencil bits
+                                      0,                // stencil bits
                                       framebuffer_info  // framebuffer info
   );
 
diff --git a/engine/src/flutter/shell/platform/android/android_context_gl.cc b/engine/src/flutter/shell/platform/android/android_context_gl.cc
index bf7f0fb4dcf..31bfc748473 100644
--- a/engine/src/flutter/shell/platform/android/android_context_gl.cc
+++ b/engine/src/flutter/shell/platform/android/android_context_gl.cc
@@ -85,7 +85,7 @@ static EGLResult<EGLConfig> ChooseEGLConfiguration(EGLDisplay display,
       EGL_BLUE_SIZE,       8,
       EGL_ALPHA_SIZE,      8,
       EGL_DEPTH_SIZE,      0,
-      EGL_STENCIL_SIZE,    8,
+      EGL_STENCIL_SIZE,    0,
       EGL_SAMPLES,         static_cast<EGLint>(msaa_samples),
       EGL_SAMPLE_BUFFERS,  sample_buffers,
       EGL_NONE,            // termination sentinel
diff --git a/engine/src/flutter/shell/platform/embedder/embedder.cc b/engine/src/flutter/shell/platform/embedder/embedder.cc
index 9eda0ffe10a..bfbf8f45b6d 100644
--- a/engine/src/flutter/shell/platform/embedder/embedder.cc
+++ b/engine/src/flutter/shell/platform/embedder/embedder.cc
@@ -621,7 +621,7 @@ static sk_sp<SkSurface> MakeSkSurfaceFromBackingStore(
       config.size.width,   // width
       config.size.height,  // height
       1,                   // sample count
-      8,                   // stencil bits
+      0,                   // stencil bits
       framebuffer_info     // framebuffer info
   );