cc: Move SkShader construction to a single spot in PaintShader

cc/paint/paint_flags.h

Index: cc/paint/paint_flags.h
diff --git a/cc/paint/paint_flags.h b/cc/paint/paint_flags.h
index c884098e555d0fa5af2f75025c4553b02bf3f2a5..b8e5fb866c7ad29092a9c10d08120dfab117a867 100644
--- a/cc/paint/paint_flags.h
+++ b/cc/paint/paint_flags.h
@@ -7,6 +7,7 @@
 
 #include "base/compiler_specific.h"
 #include "cc/paint/paint_export.h"
+#include "cc/paint/paint_shader.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkColorFilter.h"
 #include "third_party/skia/include/core/SkDrawLooper.h"
@@ -19,8 +20,6 @@
 
 namespace cc {
 
-using PaintShader = SkShader;
-
 class CC_PAINT_EXPORT PaintFlags {
  public:
   enum Style {
@@ -160,9 +159,21 @@ class CC_PAINT_EXPORT PaintFlags {
   ALWAYS_INLINE void setMaskFilter(sk_sp<SkMaskFilter> mask) {
     paint_.setMaskFilter(std::move(mask));
   }
-  ALWAYS_INLINE PaintShader* getShader() const { return paint_.getShader(); }
-  ALWAYS_INLINE void setShader(sk_sp<PaintShader> shader) {
-    paint_.setShader(std::move(shader));
+  // TODO(vmpstr): Remove this from recording calls, since we want to avoid
+  // constructing the shader until rasterization.
+  ALWAYS_INLINE SkShader* getSkShader() const { return paint_.getShader(); }
+
+  // Returns true if the shader has been set on the flags.
+  ALWAYS_INLINE bool HasShader() const { return !!paint_.getShader(); }
+
+  // Returns whether the shader is opaque. Note that it is only valid to call
+  // this function if HasShader() returns true.
+  ALWAYS_INLINE bool ShaderIsOpaque() const {
+    return paint_.getShader()->isOpaque();
+  }
+
+  ALWAYS_INLINE void setShader(std::unique_ptr<PaintShader> shader) {
+    paint_.setShader(shader ? shader->sk_shader() : nullptr);
   }
   ALWAYS_INLINE SkPathEffect* getPathEffect() const {
     return paint_.getPathEffect();