Revert of Extract most of the mutable state of SkShader into a separate Context object.

src/core/SkBitmapProcState.cpp

Index: src/core/SkBitmapProcState.cpp
diff --git a/src/core/SkBitmapProcState.cpp b/src/core/SkBitmapProcState.cpp
index 8874e7b4452308e62bcb12e964f3e9d9660ce92f..cdc582bfeec64a70791d0ecb615186b98296e639 100644
--- a/src/core/SkBitmapProcState.cpp
+++ b/src/core/SkBitmapProcState.cpp
@@ -398,7 +398,6 @@
     }
     // The above logic should have always assigned fBitmap, but in case it
     // didn't, we check for that now...
-    // TODO(dominikg): Ask humper@ if we can just use an SkASSERT(fBitmap)?
     if (NULL == fBitmap) {
         return false;
     }
@@ -481,7 +480,6 @@
     // shader will perform.
 
     fMatrixProc = this->chooseMatrixProc(trivialMatrix);
-    // TODO(dominikg): SkASSERT(fMatrixProc) instead? chooseMatrixProc never returns NULL.
     if (NULL == fMatrixProc) {
         return false;
     }
@@ -523,7 +521,6 @@
                 fPaintPMColor = SkPreMultiplyColor(paint.getColor());
                 break;
             default:
-                // TODO(dominikg): Should we ever get here? SkASSERT(false) instead?
                 return false;
         }