command_buffer: Implement CHROMIUM_framebuffer_mixed_samples extension

gpu/command_buffer/service/context_state_impl_autogen.h

Index: gpu/command_buffer/service/context_state_impl_autogen.h
diff --git a/gpu/command_buffer/service/context_state_impl_autogen.h b/gpu/command_buffer/service/context_state_impl_autogen.h
index 263841bfc857a19edc11c9b9aa1d5f45e3decaef..aca47641866d1b1d93aca2131cabf226c57a3a31 100644
--- a/gpu/command_buffer/service/context_state_impl_autogen.h
+++ b/gpu/command_buffer/service/context_state_impl_autogen.h
@@ -65,6 +65,7 @@ void ContextState::Initialize() {
   cached_color_mask_blue = true;
   color_mask_alpha = true;
   cached_color_mask_alpha = true;
+  coverage_modulation = GL_NONE;
   cull_mode = GL_BACK;
   depth_func = GL_LESS;
   depth_mask = true;
@@ -274,6 +275,9 @@ void ContextState::InitState(const ContextState* prev_state) const {
         (cached_color_mask_alpha != prev_state->cached_color_mask_alpha))
       glColorMask(cached_color_mask_red, cached_color_mask_green,
                   cached_color_mask_blue, cached_color_mask_alpha);
+    if (feature_info_->feature_flags().chromium_framebuffer_mixed_samples)
+      if ((coverage_modulation != prev_state->coverage_modulation))
+        glCoverageModulationNV(coverage_modulation);
     if ((cull_mode != prev_state->cull_mode))
       glCullFace(cull_mode);
     if ((depth_func != prev_state->depth_func))
@@ -416,6 +420,8 @@ void ContextState::InitState(const ContextState* prev_state) const {
     glClearStencil(stencil_clear);
     glColorMask(cached_color_mask_red, cached_color_mask_green,
                 cached_color_mask_blue, cached_color_mask_alpha);
+    if (feature_info_->feature_flags().chromium_framebuffer_mixed_samples)
+      glCoverageModulationNV(coverage_modulation);
     glCullFace(cull_mode);
     glDepthFunc(depth_func);
     glDepthMask(cached_depth_mask);
@@ -593,6 +599,12 @@ bool ContextState::GetStateAsGLint(GLenum pname,
         params[3] = static_cast<GLint>(color_mask_alpha);
       }
       return true;
+    case GL_COVERAGE_MODULATION_CHROMIUM:
+      *num_written = 1;
+      if (params) {
+        params[0] = static_cast<GLint>(coverage_modulation);
+      }
+      return true;
     case GL_CULL_FACE_MODE:
       *num_written = 1;
       if (params) {
@@ -1025,6 +1037,12 @@ bool ContextState::GetStateAsGLfloat(GLenum pname,
         params[3] = static_cast<GLfloat>(color_mask_alpha);
       }
       return true;
+    case GL_COVERAGE_MODULATION_CHROMIUM:
+      *num_written = 1;
+      if (params) {
+        params[0] = static_cast<GLfloat>(coverage_modulation);
+      }
+      return true;
     case GL_CULL_FACE_MODE:
       *num_written = 1;
       if (params) {