mix-blend-mode implementation for accelerated layers

cc/quads/shared_quad_state.cc

Index: cc/quads/shared_quad_state.cc
diff --git a/cc/quads/shared_quad_state.cc b/cc/quads/shared_quad_state.cc
index 6a53d9f6a9f8d1a410deacb6ae8fc44d745d28ed..3c568b127546fb2f77817a319cdec3819a09c09a 100644
--- a/cc/quads/shared_quad_state.cc
+++ b/cc/quads/shared_quad_state.cc
@@ -10,7 +10,34 @@
 
 namespace cc {
 
-SharedQuadState::SharedQuadState() : is_clipped(false), opacity(0.f) {}
+namespace {
+
+const char* BlendModeToString(SkXfermode::Mode blendMode) {
+  switch (blendMode) {
+  case SkXfermode::kMultiply_Mode:    return "multiply";
+  case SkXfermode::kScreen_Mode:      return "screen";
+  case SkXfermode::kOverlay_Mode:     return "overlay";
+  case SkXfermode::kDarken_Mode:      return "darken";
+  case SkXfermode::kLighten_Mode:     return "lighten";
+  case SkXfermode::kColorDodge_Mode:  return "color-dodge";
+  case SkXfermode::kColorBurn_Mode:   return "color-burn";
+  case SkXfermode::kHardLight_Mode:   return "hard-light";
+  case SkXfermode::kSoftLight_Mode:   return "soft-light";
+  case SkXfermode::kDifference_Mode:  return "difference";
+  case SkXfermode::kExclusion_Mode:   return "exclusion";
+  case SkXfermode::kHue_Mode:         return "hue";
+  case SkXfermode::kSaturation_Mode:  return "saturation";
+  case SkXfermode::kColor_Mode:       return "color";
+  case SkXfermode::kLuminosity_Mode:  return "luminosity";
+  default:                            return "normal";
+  }
+}
+
+}  // namespace
+
+SharedQuadState::SharedQuadState() : is_clipped(false),
+                                     opacity(0.f),
+                                     blend_mode(SkXfermode::kSrcOver_Mode) {}
 
 SharedQuadState::~SharedQuadState() {
   TRACE_EVENT_OBJECT_DELETED_WITH_ID(
@@ -32,13 +59,15 @@ void SharedQuadState::SetAll(
     gfx::Rect visible_content_rect,
     gfx::Rect clip_rect,
     bool is_clipped,
-    float opacity) {
+    float opacity,
+    SkXfermode::Mode blend_mode) {
   this->content_to_target_transform = content_to_target_transform;
   this->content_bounds = content_bounds;
   this->visible_content_rect = visible_content_rect;
   this->clip_rect = clip_rect;
   this->is_clipped = is_clipped;
   this->opacity = opacity;
+  this->blend_mode = blend_mode;
 }
 
 scoped_ptr<base::Value> SharedQuadState::AsValue() const {
@@ -52,6 +81,7 @@ scoped_ptr<base::Value> SharedQuadState::AsValue() const {
   value->SetBoolean("is_clipped", is_clipped);
   value->Set("clip_rect", MathUtil::AsValue(clip_rect).release());
   value->SetDouble("opacity", opacity);
+  value->SetString("blend_mode", BlendModeToString(blend_mode));
   TracedValue::MakeDictIntoImplicitSnapshotWithCategory(
       TRACE_DISABLED_BY_DEFAULT("cc.debug.quads"),
       value.get(), "cc::SharedQuadState", this);