add more checks for computing clamp counts, remove dead code

src/effects/gradients/SkClampRange.cpp

 
 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "SkClampRange.h"
@@ skipping 59 matching lines @@
         fCount1 = fCount2 = 0;
         fCount0 = count;
         return;
     }
     if (fx >= kFracMax_SkGradFixed && ex >= kFracMax_SkGradFixed) {
         fCount0 = fCount1 = 0;
         fCount2 = count;
         return;
     }
 
-    int extraCount = 0;
-
     // now make ex be 1 past the last computed value
     ex += dx;
 
     bool doSwap = dx < 0;
 
     if (doSwap) {
         ex -= dx;
         fx -= dx;
         SkTSwap(fx, ex);
         dx = -dx;
     }
 
 
     fCount0 = chop(fx, 0, ex, dx, count);
+    SkASSERT(fCount0 >= 0);
+    SkASSERT(fCount0 <= count);
     count -= fCount0;
     fx += fCount0 * dx;
     SkASSERT(fx >= 0);
     SkASSERT(fCount0 == 0 || (fx - dx) < 0);
     fCount1 = chop(fx, kFracMax_SkGradFixed, ex, dx, count);
+    SkASSERT(fCount1 >= 0);
+    SkASSERT(fCount1 <= count);
     count -= fCount1;
     fCount2 = count;
 
 #ifdef SK_DEBUG
     fx += fCount1 * dx;
     SkASSERT(fx <= ex);
     if (fCount2 > 0) {
         SkASSERT(fx >= kFracMax_SkGradFixed);
         if (fCount1 > 0) {
             SkASSERT(fx - dx < kFracMax_SkGradFixed);
         }
     }
 #endif
 
     if (doSwap) {
         SkTSwap(fCount0, fCount2);
         SkTSwap(fV0, fV1);
         dx = -dx;
     }
 
     if (fCount1 > 0) {
         fFx1 = fx0 + fCount0 * dx;
     }
-
-    if (dx > 0) {
-        fCount2 += extraCount;
-    } else {
-        fCount0 += extraCount;
-    }
 }