don't get dismayed by negative scales for HQ

src/core/SkBitmapController.cpp

Index: src/core/SkBitmapController.cpp
diff --git a/src/core/SkBitmapController.cpp b/src/core/SkBitmapController.cpp
index f4d352507aa616dba7012a677dfce95ad0cad52d..e11a840976d62935307729b6694cc09114cd6678 100644
--- a/src/core/SkBitmapController.cpp
+++ b/src/core/SkBitmapController.cpp
@@ -65,7 +65,8 @@ static inline bool cache_size_okay(const SkBitmapProvider& provider, const SkMat
     // return ((origBitmapSize * matrixScaleFactor) < maximumAllocationSize);
     // Skip the division step:
     const size_t size = provider.info().getSafeSize(provider.info().minRowBytes());
-    return size < (maximumAllocation * invMat.getScaleX() * invMat.getScaleY());
+    SkScalar invScaleSqr = SkScalarAbs(invMat.getScaleX() * invMat.getScaleY());
+    return size < (maximumAllocation * invScaleSqr);
 }
 
 /*
@@ -97,6 +98,9 @@ bool SkDefaultBitmapControllerState::processHQRequest(const SkBitmapProvider& pr
         invScaleX = scale.width();
         invScaleY = scale.height();
     }
+    invScaleX = SkScalarAbs(invScaleX);

[vmpstr, 2016/02/04 00:59:04]

This is the only bit that requires some thought for me. I think this is OK,
since we won't undo the flip as a result (ie the matrix would retain the fact
that the image is flipped). 

+    invScaleY = SkScalarAbs(invScaleY);
+
     if (SkScalarNearlyEqual(invScaleX, 1) && SkScalarNearlyEqual(invScaleY, 1)) {
         return false; // no need for HQ
     }