add some asserts for mipmaps, and cleanup fFilterLevel if mipping failed

src/core/SkBitmapProcState.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 "SkBitmapProcState.h"
 #include "SkColorPriv.h"
 #include "SkFilterProc.h"
@@ skipping 245 matching lines @@
         const SkMipMap* mip = NULL;
 
         SkASSERT(NULL == fScaledCacheID);
         fScaledCacheID = SkScaledImageCache::FindAndLockMip(fOrigBitmap, &mip);
         if (!fScaledCacheID) {
             SkASSERT(NULL == mip);
             mip = SkMipMap::Build(fOrigBitmap);
             if (mip) {
                 fScaledCacheID = SkScaledImageCache::AddAndLockMip(fOrigBitmap,
                                                                    mip);
+                SkASSERT(mip->getRefCnt() > 1);
                 mip->unref();   // the cache took a ref
                 SkASSERT(fScaledCacheID);
             }
         } else {
             SkASSERT(mip);
         }
 
         if (mip) {
             SkScalar levelScale = SkScalarInvert(SkScalarSqrt(scaleSqd));
             SkMipMap::Level level;
@@ skipping 120 matching lines @@
             return false;
         }
     }
     // 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;
     }
 
+    // If we are "still" kMedium_FilterLevel, then the request was not fulfilled by possiblyScale,
+    // so we downgrade to kLow (so the rest of the sniffing code can assume that)
+    if (SkPaint::kMedium_FilterLevel == fFilterLevel) {
+        fFilterLevel = SkPaint::kLow_FilterLevel;
+    }
+
     bool trivialMatrix = (fInvMatrix.getType() & ~SkMatrix::kTranslate_Mask) == 0;
     bool clampClamp = SkShader::kClamp_TileMode == fTileModeX &&
                       SkShader::kClamp_TileMode == fTileModeY;
 
     if (!(clampClamp || trivialMatrix)) {
         fInvMatrix.postIDiv(fOrigBitmap.width(), fOrigBitmap.height());
     }
 
     // Now that all possible changes to the matrix have taken place, check
     // to see if we're really close to a no-scale matrix.  If so, explicitly
@@ skipping 620 matching lines @@
     } else {
         size >>= 2;
     }
 
     if (fFilterLevel != SkPaint::kNone_FilterLevel) {
         size >>= 1;
     }
 
     return size;
 }