Implement external stencil for Android WebView

Add an OutputSurface::ApplyExternalStencil method.
Android WebView implements this method on the render thread
and applies the stencil parameters read in functor, through
the command buffer client.

BUG=574570
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/1564703005

Cr-Commit-Position: refs/heads/master@{#368468}

12 files changed, 105 insertions, 62 deletions

diff --git a/android_webview/browser/aw_render_thread_context_provider.cc b/android_webview/browser/aw_render_thread_context_provider.cc
index acc6e36..27dbf714 100644
--- a/android_webview/browser/aw_render_thread_context_provider.cc
+++ b/android_webview/browser/aw_render_thread_context_provider.cc
@@ -53,7 +53,7 @@ AwRenderThreadContextProvider::AwRenderThreadContextProvider(
   blink::WebGraphicsContext3D::Attributes attributes;
   attributes.antialias = false;
   attributes.depth = false;
-  attributes.stencil = false;
+  attributes.stencil = true;
   attributes.shareResources = true;
   attributes.noAutomaticFlushes = true;
   gpu::gles2::ContextCreationAttribHelper attribs_for_gles2;
diff --git a/android_webview/browser/hardware_renderer.cc b/android_webview/browser/hardware_renderer.cc
index cde6161..5688b1c 100644
--- a/android_webview/browser/hardware_renderer.cc
+++ b/android_webview/browser/hardware_renderer.cc
@@ -87,8 +87,8 @@ void HardwareRenderer::CommitFrame() {
   DCHECK(!child_frame_->frame->gl_frame_data);
 }
 
-void HardwareRenderer::DrawGL(bool stencil_enabled,
-                              AwDrawGLInfo* draw_info) {
+void HardwareRenderer::DrawGL(AwDrawGLInfo* draw_info,
+                              const ScopedAppGLStateRestore& gl_state) {
   TRACE_EVENT0("android_webview", "HardwareRenderer::DrawGL");
 
   // We need to watch if the current Android context has changed and enforce
@@ -211,7 +211,7 @@ void HardwareRenderer::DrawGL(bool stencil_enabled,
     output_surface_ = output_surface_holder.get();
     display_->Initialize(std::move(output_surface_holder), nullptr);
   }
-  output_surface_->SetExternalStencilTest(stencil_enabled);
+  output_surface_->SetGLState(gl_state);
   display_->SetExternalClip(clip);
   display_->DrawAndSwap();
 }
diff --git a/android_webview/browser/hardware_renderer.h b/android_webview/browser/hardware_renderer.h
index a5c47e8..eb1ccc9 100644
--- a/android_webview/browser/hardware_renderer.h
+++ b/android_webview/browser/hardware_renderer.h
@@ -26,6 +26,7 @@ namespace android_webview {
 class AwGLSurface;
 class ChildFrame;
 class ParentOutputSurface;
+class ScopedAppGLStateRestore;
 
 class HardwareRenderer : public cc::DisplayClient,
                          public cc::SurfaceFactoryClient {
@@ -33,8 +34,7 @@ class HardwareRenderer : public cc::DisplayClient,
   explicit HardwareRenderer(SharedRendererState* state);
   ~HardwareRenderer() override;
 
-  void DrawGL(bool stencil_enabled,
-              AwDrawGLInfo* draw_info);
+  void DrawGL(AwDrawGLInfo* draw_info, const ScopedAppGLStateRestore& gl_state);
   void CommitFrame();
 
   void SetBackingFrameBufferObject(int framebuffer_binding_ext);
diff --git a/android_webview/browser/parent_output_surface.cc b/android_webview/browser/parent_output_surface.cc
index 4a777cb..e73fecf 100644
--- a/android_webview/browser/parent_output_surface.cc
+++ b/android_webview/browser/parent_output_surface.cc
@@ -12,6 +12,7 @@ namespace android_webview {
 ParentOutputSurface::ParentOutputSurface(
     scoped_refptr<cc::ContextProvider> context_provider)
     : cc::OutputSurface(context_provider) {
+  stencil_state_.stencil_test_enabled = false;
 }
 
 ParentOutputSurface::~ParentOutputSurface() {
@@ -34,4 +35,28 @@ void ParentOutputSurface::SwapBuffers(cc::CompositorFrame* frame) {
   client_->DidSwapBuffers();
 }
 
+void ParentOutputSurface::ApplyExternalStencil() {
+  DCHECK(stencil_state_.stencil_test_enabled);
+  gpu::gles2::GLES2Interface* gl = context_provider()->ContextGL();
+  gl->StencilFuncSeparate(GL_FRONT, stencil_state_.stencil_front_func,
+                          stencil_state_.stencil_front_mask,
+                          stencil_state_.stencil_front_ref);
+  gl->StencilFuncSeparate(GL_BACK, stencil_state_.stencil_back_func,
+                          stencil_state_.stencil_back_mask,
+                          stencil_state_.stencil_back_ref);
+  gl->StencilMaskSeparate(GL_FRONT, stencil_state_.stencil_front_writemask);
+  gl->StencilMaskSeparate(GL_BACK, stencil_state_.stencil_back_writemask);
+  gl->StencilOpSeparate(GL_FRONT, stencil_state_.stencil_front_fail_op,
+                        stencil_state_.stencil_front_z_fail_op,
+                        stencil_state_.stencil_front_z_pass_op);
+  gl->StencilOpSeparate(GL_BACK, stencil_state_.stencil_back_fail_op,
+                        stencil_state_.stencil_back_z_fail_op,
+                        stencil_state_.stencil_back_z_pass_op);
+}
+
+void ParentOutputSurface::SetGLState(const ScopedAppGLStateRestore& gl_state) {
+  stencil_state_ = gl_state.stencil_state();
+  SetExternalStencilTest(stencil_state_.stencil_test_enabled);
+}
+
 }  // namespace android_webview
diff --git a/android_webview/browser/parent_output_surface.h b/android_webview/browser/parent_output_surface.h
index 0467f2a..f69598e 100644
--- a/android_webview/browser/parent_output_surface.h
+++ b/android_webview/browser/parent_output_surface.h
@@ -5,6 +5,7 @@
 #ifndef ANDROID_WEBVIEW_BROWSER_PARENT_OUTPUT_SURFACE_H_
 #define ANDROID_WEBVIEW_BROWSER_PARENT_OUTPUT_SURFACE_H_
 
+#include "android_webview/browser/scoped_app_gl_state_restore.h"
 #include "base/macros.h"
 #include "cc/output/output_surface.h"
 
@@ -22,9 +23,13 @@ class ParentOutputSurface : NON_EXPORTED_BASE(public cc::OutputSurface) {
                float scale_factor,
                bool has_alpha) override;
   void SwapBuffers(cc::CompositorFrame* frame) override;
-  using cc::OutputSurface::SetExternalStencilTest;
+  void ApplyExternalStencil() override;
+
+  void SetGLState(const ScopedAppGLStateRestore& gl_state);
 
  private:
+  StencilState stencil_state_;
+
   DISALLOW_COPY_AND_ASSIGN(ParentOutputSurface);
 };
 
diff --git a/android_webview/browser/scoped_app_gl_state_restore.cc b/android_webview/browser/scoped_app_gl_state_restore.cc
index 0f45ca3..caa2387 100644
--- a/android_webview/browser/scoped_app_gl_state_restore.cc
+++ b/android_webview/browser/scoped_app_gl_state_restore.cc
@@ -72,10 +72,10 @@ namespace internal {
 
 class ScopedAppGLStateRestoreImpl {
  public:
-  ScopedAppGLStateRestoreImpl(ScopedAppGLStateRestore::CallMode mode);
+  explicit ScopedAppGLStateRestoreImpl(ScopedAppGLStateRestore::CallMode mode);
   ~ScopedAppGLStateRestoreImpl();
 
-  bool stencil_enabled() const { return stencil_test_; }
+  StencilState stencil_state() const { return stencil_state_; }
   GLint framebuffer_binding_ext() const { return framebuffer_binding_ext_; }
 
  private:
@@ -135,22 +135,7 @@ class ScopedAppGLStateRestoreImpl {
   GLboolean scissor_test_;
   GLint scissor_box_[4];
 
-  GLboolean stencil_test_;
-  GLint stencil_front_func_;
-  GLint stencil_front_ref_;
-  GLint stencil_front_mask_;
-  GLint stencil_back_func_;
-  GLint stencil_back_ref_;
-  GLint stencil_back_mask_;
-  GLint stencil_clear_;
-  GLint stencil_front_writemask_;
-  GLint stencil_back_writemask_;
-  GLint stencil_front_fail_op_;
-  GLint stencil_front_z_fail_op_;
-  GLint stencil_front_z_pass_op_;
-  GLint stencil_back_fail_op_;
-  GLint stencil_back_z_fail_op_;
-  GLint stencil_back_z_pass_op_;
+  StencilState stencil_state_;
 
   GLint framebuffer_binding_ext_;
 
@@ -239,22 +224,27 @@ ScopedAppGLStateRestoreImpl::ScopedAppGLStateRestoreImpl(
   glGetBooleanv(GL_SAMPLE_ALPHA_TO_COVERAGE, &enable_sample_alpha_to_coverage_);
   glGetBooleanv(GL_SAMPLE_COVERAGE, &enable_sample_coverage_);
 
-  glGetBooleanv(GL_STENCIL_TEST, &stencil_test_);
-  glGetIntegerv(GL_STENCIL_FUNC, &stencil_front_func_);
-  glGetIntegerv(GL_STENCIL_VALUE_MASK, &stencil_front_mask_);
-  glGetIntegerv(GL_STENCIL_REF, &stencil_front_ref_);
-  glGetIntegerv(GL_STENCIL_BACK_FUNC, &stencil_back_func_);
-  glGetIntegerv(GL_STENCIL_BACK_VALUE_MASK, &stencil_back_mask_);
-  glGetIntegerv(GL_STENCIL_BACK_REF, &stencil_back_ref_);
-  glGetIntegerv(GL_STENCIL_CLEAR_VALUE, &stencil_clear_);
-  glGetIntegerv(GL_STENCIL_WRITEMASK, &stencil_front_writemask_);
-  glGetIntegerv(GL_STENCIL_BACK_WRITEMASK, &stencil_back_writemask_);
-  glGetIntegerv(GL_STENCIL_FAIL, &stencil_front_fail_op_);
-  glGetIntegerv(GL_STENCIL_PASS_DEPTH_FAIL, &stencil_front_z_fail_op_);
-  glGetIntegerv(GL_STENCIL_PASS_DEPTH_PASS, &stencil_front_z_pass_op_);
-  glGetIntegerv(GL_STENCIL_BACK_FAIL, &stencil_back_fail_op_);
-  glGetIntegerv(GL_STENCIL_BACK_PASS_DEPTH_FAIL, &stencil_back_z_fail_op_);
-  glGetIntegerv(GL_STENCIL_BACK_PASS_DEPTH_PASS, &stencil_back_z_pass_op_);
+  glGetBooleanv(GL_STENCIL_TEST, &stencil_state_.stencil_test_enabled);
+  glGetIntegerv(GL_STENCIL_FUNC, &stencil_state_.stencil_front_func);
+  glGetIntegerv(GL_STENCIL_VALUE_MASK, &stencil_state_.stencil_front_mask);
+  glGetIntegerv(GL_STENCIL_REF, &stencil_state_.stencil_front_ref);
+  glGetIntegerv(GL_STENCIL_BACK_FUNC, &stencil_state_.stencil_back_func);
+  glGetIntegerv(GL_STENCIL_BACK_VALUE_MASK, &stencil_state_.stencil_back_mask);
+  glGetIntegerv(GL_STENCIL_BACK_REF, &stencil_state_.stencil_back_ref);
+  glGetIntegerv(GL_STENCIL_CLEAR_VALUE, &stencil_state_.stencil_clear);
+  glGetIntegerv(GL_STENCIL_WRITEMASK, &stencil_state_.stencil_front_writemask);
+  glGetIntegerv(GL_STENCIL_BACK_WRITEMASK,
+                &stencil_state_.stencil_back_writemask);
+  glGetIntegerv(GL_STENCIL_FAIL, &stencil_state_.stencil_front_fail_op);
+  glGetIntegerv(GL_STENCIL_PASS_DEPTH_FAIL,
+                &stencil_state_.stencil_front_z_fail_op);
+  glGetIntegerv(GL_STENCIL_PASS_DEPTH_PASS,
+                &stencil_state_.stencil_front_z_pass_op);
+  glGetIntegerv(GL_STENCIL_BACK_FAIL, &stencil_state_.stencil_back_fail_op);
+  glGetIntegerv(GL_STENCIL_BACK_PASS_DEPTH_FAIL,
+                &stencil_state_.stencil_back_z_fail_op);
+  glGetIntegerv(GL_STENCIL_BACK_PASS_DEPTH_PASS,
+                &stencil_state_.stencil_back_z_pass_op);
 
   glGetIntegerv(GL_FRAMEBUFFER_BINDING_EXT, &framebuffer_binding_ext_);
 
@@ -402,22 +392,22 @@ ScopedAppGLStateRestoreImpl::~ScopedAppGLStateRestoreImpl() {
       break;
   }
 
-  GLEnableDisable(GL_STENCIL_TEST, stencil_test_);
-  glStencilFuncSeparate(
-      GL_FRONT, stencil_front_func_, stencil_front_mask_, stencil_front_ref_);
-  glStencilFuncSeparate(
-      GL_BACK, stencil_back_func_, stencil_back_mask_, stencil_back_ref_);
-  glClearStencil(stencil_clear_);
-  glStencilMaskSeparate(GL_FRONT, stencil_front_writemask_);
-  glStencilMaskSeparate(GL_BACK, stencil_back_writemask_);
-  glStencilOpSeparate(GL_FRONT,
-                      stencil_front_fail_op_,
-                      stencil_front_z_fail_op_,
-                      stencil_front_z_pass_op_);
-  glStencilOpSeparate(GL_BACK,
-                      stencil_back_fail_op_,
-                      stencil_back_z_fail_op_,
-                      stencil_back_z_pass_op_);
+  GLEnableDisable(GL_STENCIL_TEST, stencil_state_.stencil_test_enabled);
+  glStencilFuncSeparate(GL_FRONT, stencil_state_.stencil_front_func,
+                        stencil_state_.stencil_front_mask,
+                        stencil_state_.stencil_front_ref);
+  glStencilFuncSeparate(GL_BACK, stencil_state_.stencil_back_func,
+                        stencil_state_.stencil_back_mask,
+                        stencil_state_.stencil_back_ref);
+  glClearStencil(stencil_state_.stencil_clear);
+  glStencilMaskSeparate(GL_FRONT, stencil_state_.stencil_front_writemask);
+  glStencilMaskSeparate(GL_BACK, stencil_state_.stencil_back_writemask);
+  glStencilOpSeparate(GL_FRONT, stencil_state_.stencil_front_fail_op,
+                      stencil_state_.stencil_front_z_fail_op,
+                      stencil_state_.stencil_front_z_pass_op);
+  glStencilOpSeparate(GL_BACK, stencil_state_.stencil_back_fail_op,
+                      stencil_state_.stencil_back_z_fail_op,
+                      stencil_state_.stencil_back_z_pass_op);
 
   // Do not leak GLError out of chromium.
   ClearGLErrors(true, "Chromium GLError");
@@ -431,8 +421,8 @@ ScopedAppGLStateRestore::ScopedAppGLStateRestore(CallMode mode)
 
 ScopedAppGLStateRestore::~ScopedAppGLStateRestore() {}
 
-bool ScopedAppGLStateRestore::stencil_enabled() const {
-  return impl_->stencil_enabled();
+StencilState ScopedAppGLStateRestore::stencil_state() const {
+  return impl_->stencil_state();
 }
 int ScopedAppGLStateRestore::framebuffer_binding_ext() const {
   return impl_->framebuffer_binding_ext();
diff --git a/android_webview/browser/scoped_app_gl_state_restore.h b/android_webview/browser/scoped_app_gl_state_restore.h
index 7639884..f2356f7 100644
--- a/android_webview/browser/scoped_app_gl_state_restore.h
+++ b/android_webview/browser/scoped_app_gl_state_restore.h
@@ -17,6 +17,25 @@ namespace internal {
 class ScopedAppGLStateRestoreImpl;
 }
 
+struct StencilState {
+  unsigned char stencil_test_enabled;
+  int stencil_front_func;
+  int stencil_front_ref;
+  int stencil_front_mask;
+  int stencil_back_func;
+  int stencil_back_ref;
+  int stencil_back_mask;
+  int stencil_clear;
+  int stencil_front_writemask;
+  int stencil_back_writemask;
+  int stencil_front_fail_op;
+  int stencil_front_z_fail_op;
+  int stencil_front_z_pass_op;
+  int stencil_back_fail_op;
+  int stencil_back_z_fail_op;
+  int stencil_back_z_pass_op;
+};
+
 // This class is not thread safe and should only be used on the UI thread.
 class ScopedAppGLStateRestore {
  public:
@@ -28,7 +47,7 @@ class ScopedAppGLStateRestore {
   explicit ScopedAppGLStateRestore(CallMode mode);
   ~ScopedAppGLStateRestore();
 
-  bool stencil_enabled() const;
+  StencilState stencil_state() const;
   int framebuffer_binding_ext() const;
 
  private:
diff --git a/android_webview/browser/shared_renderer_state.cc b/android_webview/browser/shared_renderer_state.cc
index 56c55a1..018b84b 100644
--- a/android_webview/browser/shared_renderer_state.cc
+++ b/android_webview/browser/shared_renderer_state.cc
@@ -300,7 +300,7 @@ void SharedRendererState::DrawGL(AwDrawGLInfo* draw_info) {
     return;
   }
 
-  hardware_renderer_->DrawGL(state_restore.stencil_enabled(), draw_info);
+  hardware_renderer_->DrawGL(draw_info, state_restore);
   DeferredGpuCommandService::GetInstance()->PerformIdleWork(false);
 }
 
diff --git a/cc/output/gl_renderer.cc b/cc/output/gl_renderer.cc
index 0183068..4dc802f 100644
--- a/cc/output/gl_renderer.cc
+++ b/cc/output/gl_renderer.cc
@@ -2926,8 +2926,8 @@ void GLRenderer::BindFramebufferToOutputSurface(DrawingFrame* frame) {
   output_surface_->BindFramebuffer();
 
   if (output_surface_->HasExternalStencilTest()) {
+    output_surface_->ApplyExternalStencil();
     SetStencilEnabled(true);
-    gl_->StencilFunc(GL_EQUAL, 1, 1);
   } else {
     SetStencilEnabled(false);
   }
diff --git a/cc/output/output_surface.cc b/cc/output/output_surface.cc
index 13e41d3..85372ce 100644
--- a/cc/output/output_surface.cc
+++ b/cc/output/output_surface.cc
@@ -191,6 +191,8 @@ bool OutputSurface::HasExternalStencilTest() const {
   return external_stencil_test_enabled_;
 }
 
+void OutputSurface::ApplyExternalStencil() {}
+
 bool OutputSurface::BindToClient(OutputSurfaceClient* client) {
   DCHECK(client_thread_checker_.CalledOnValidThread());
   DCHECK(client);
diff --git a/cc/output/output_surface.h b/cc/output/output_surface.h
index f135e50..0b06800 100644
--- a/cc/output/output_surface.h
+++ b/cc/output/output_surface.h
@@ -92,6 +92,7 @@ class CC_EXPORT OutputSurface : public base::trace_event::MemoryDumpProvider {
   }
 
   virtual bool HasExternalStencilTest() const;
+  virtual void ApplyExternalStencil();
 
   // Obtain the 3d context or the software device associated with this output
   // surface. Either of these may return a null pointer, but not both.
diff --git a/cc/output/renderer_pixeltest.cc b/cc/output/renderer_pixeltest.cc
index 6c5e255..f5afaea 100644
--- a/cc/output/renderer_pixeltest.cc
+++ b/cc/output/renderer_pixeltest.cc
@@ -1889,6 +1889,7 @@ class ExternalStencilPixelTest : public GLRendererPixelTest {
                 device_viewport_size_.width(),
                 device_viewport_size_.height());
     gl->Clear(GL_STENCIL_BUFFER_BIT);
+    gl->StencilFunc(GL_EQUAL, 1, 1);
   }
 };