[cc] Add SkBlendMode::kDstIn support to cc::Layer

cc/output/gl_renderer.cc

 // Copyright 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/output/gl_renderer.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 92 matching lines @@
     default:
       NOTREACHED();
       return SAMPLER_TYPE_2D;
   }
 }
 
 BlendMode BlendModeFromSkXfermode(SkBlendMode mode) {
   switch (mode) {
     case SkBlendMode::kSrcOver:
       return BLEND_MODE_NORMAL;
+    case SkBlendMode::kDstIn:
+      return BLEND_MODE_DESTINATION_IN;
     case SkBlendMode::kScreen:
       return BLEND_MODE_SCREEN;
     case SkBlendMode::kOverlay:
       return BLEND_MODE_OVERLAY;
     case SkBlendMode::kDarken:
       return BLEND_MODE_DARKEN;
     case SkBlendMode::kLighten:
       return BLEND_MODE_LIGHTEN;
     case SkBlendMode::kColorDodge:
       return BLEND_MODE_COLOR_DODGE;
@@ skipping 584 matching lines @@
   }
 
   // Force a flush of the Skia pipeline before we switch back to the compositor
   // context.
   image->getTextureHandle(true);
   CHECK(image->isTextureBacked());
   return image;
 }
 
 bool GLRenderer::CanApplyBlendModeUsingBlendFunc(SkBlendMode blend_mode) {
-  return use_blend_equation_advanced_ || blend_mode == SkBlendMode::kScreen ||
-         blend_mode == SkBlendMode::kSrcOver;
+  return use_blend_equation_advanced_ || blend_mode == SkBlendMode::kSrcOver ||
+         blend_mode == SkBlendMode::kDstIn ||
+         blend_mode == SkBlendMode::kScreen;
 }
 
 void GLRenderer::ApplyBlendModeUsingBlendFunc(SkBlendMode blend_mode) {
-  DCHECK(CanApplyBlendModeUsingBlendFunc(blend_mode));
-
   // Any modes set here must be reset in RestoreBlendFuncToDefault
-  if (use_blend_equation_advanced_) {
+  if (blend_mode == SkBlendMode::kSrcOver) {
+    // Left no-op intentionally.
+  } else if (blend_mode == SkBlendMode::kDstIn) {
+    gl_->BlendFunc(GL_ZERO, GL_SRC_ALPHA);
+  } else if (blend_mode == SkBlendMode::kScreen) {
+    gl_->BlendFunc(GL_ONE_MINUS_DST_COLOR, GL_ONE);
+  } else {
+    DCHECK(use_blend_equation_advanced_);
     GLenum equation = GL_FUNC_ADD;
-
     switch (blend_mode) {
       case SkBlendMode::kScreen:
         equation = GL_SCREEN_KHR;
         break;
       case SkBlendMode::kOverlay:
         equation = GL_OVERLAY_KHR;
         break;
       case SkBlendMode::kDarken:
         equation = GL_DARKEN_KHR;
         break;
@@ skipping 27 matching lines @@
       case SkBlendMode::kSaturation:
         equation = GL_HSL_SATURATION_KHR;
         break;
       case SkBlendMode::kColor:
         equation = GL_HSL_COLOR_KHR;
         break;
       case SkBlendMode::kLuminosity:
         equation = GL_HSL_LUMINOSITY_KHR;
         break;
       default:
+        NOTREACHED() << "Unexpected blend mode: SkBlendMode::k"
+                     << SkBlendMode_Name(blend_mode);
         return;
     }
-
     gl_->BlendEquation(equation);
-  } else {
-    if (blend_mode == SkBlendMode::kScreen) {
-      gl_->BlendFunc(GL_ONE_MINUS_DST_COLOR, GL_ONE);
-    }
   }
 }
 
 void GLRenderer::RestoreBlendFuncToDefault(SkBlendMode blend_mode) {
-  if (blend_mode == SkBlendMode::kSrcOver)
-    return;
-
-  if (use_blend_equation_advanced_) {
-    gl_->BlendEquation(GL_FUNC_ADD);
-  } else {
-    gl_->BlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
+  switch (blend_mode) {
+    case SkBlendMode::kSrcOver:
+      break;
+    case SkBlendMode::kDstIn:
+    case SkBlendMode::kScreen:
+      gl_->BlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
+      break;
+    default:
+      DCHECK(use_blend_equation_advanced_);
+      gl_->BlendEquation(GL_FUNC_ADD);
   }
 }
 
 bool GLRenderer::ShouldApplyBackgroundFilters(
     const RenderPassDrawQuad* quad,
     const FilterOperations* background_filters) {
   if (!background_filters)
     return false;
   DCHECK(!background_filters->IsEmpty());
 
@@ skipping 2786 matching lines @@
     return;
 
   // Report GPU overdraw as a percentage of |max_result|.
   TRACE_COUNTER1(
       TRACE_DISABLED_BY_DEFAULT("cc.debug.overdraw"), "GPU Overdraw",
       (std::accumulate(overdraw->begin(), overdraw->end(), 0) * 100) /
           max_result);
 }
 
 }  // namespace cc