Revert of Remove GP from drawstate, revision of invariant output for GP

include/gpu/GrProcessor.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrProcessor_DEFINED
 #define GrProcessor_DEFINED
 
@@ skipping 43 matching lines @@
     Dynamically allocated GrProcessors are managed by a per-thread memory pool. The ref count of an
     processor must reach 0 before the thread terminates and the pool is destroyed. To create a
     static processor use the helper macro GR_CREATE_STATIC_PROCESSOR declared below.
  */
 class GrProcessor : public GrProgramElement {
 public:
     SK_DECLARE_INST_COUNT(GrProcessor)
 
     virtual ~GrProcessor();
 
+    /**
+     * This function is used to perform optimizations. When called the invarientOuput param
+     * indicate whether the input components to this processor in the FS will have known values.
+     * In inout the validFlags member is a bitfield of GrColorComponentFlags. The isSingleComponent
+     * member indicates whether the input will be 1 or 4 bytes. The function updates the members of
+     * inout to indicate known values of its output. A component of the color member only has
+     * meaning if the corresponding bit in validFlags is set.
+     */
+    void computeInvariantOutput(GrInvariantOutput* inout) const; 
+
     /** Human-meaningful string to identify this prcoessor; may be embedded
         in generated shader code. */
     virtual const char* name() const = 0;
 
     int numTextures() const { return fTextureAccesses.count(); }
 
     /** Returns the access pattern for the texture at index. index must be valid according to
         numTextures(). */
     const GrTextureAccess& textureAccess(int index) const { return *fTextureAccesses[index]; }
 
@@ skipping 41 matching lines @@
     void setWillReadFragmentPosition() { fWillReadFragmentPosition = true; }
 
     template <typename PROC_SUBCLASS> void initClassID() {
          static uint32_t kClassID = GenClassID();
          fClassID = kClassID;
     }
 
     uint32_t fClassID;
 
 private:
+    /** 
+     * Subclass implements this to support getConstantColorComponents(...).
+     */
+    virtual void onComputeInvariantOutput(GrInvariantOutput* inout) const = 0;
+    
     static uint32_t GenClassID() {
         // fCurrProcessorClassID has been initialized to kIllegalProcessorClassID. The
         // atomic inc returns the old value not the incremented value. So we add
         // 1 to the returned value.
         uint32_t id = static_cast<uint32_t>(sk_atomic_inc(&gCurrProcessorClassID)) + 1;
         if (!id) {
             SkFAIL("This should never wrap as it should only be called once for each GrProcessor "
                    "subclass.");
         }
         return id;
@@ skipping 13 matching lines @@
 /**
  * This creates a processor outside of the memory pool. The processor's destructor will be called
  * at global destruction time. NAME will be the name of the created instance.
  */
 #define GR_CREATE_STATIC_PROCESSOR(NAME, PROC_CLASS, ARGS)                                 \
 static SkAlignedSStorage<sizeof(PROC_CLASS)> g_##NAME##_Storage;                           \
 static PROC_CLASS* NAME SkNEW_PLACEMENT_ARGS(g_##NAME##_Storage.get(), PROC_CLASS, ARGS);  \
 static SkAutoTDestroy<GrProcessor> NAME##_ad(NAME);
 
 #endif