make allocPixels throw on failure

src/effects/SkMorphologyImageFilter.cpp

Index: src/effects/SkMorphologyImageFilter.cpp
diff --git a/src/effects/SkMorphologyImageFilter.cpp b/src/effects/SkMorphologyImageFilter.cpp
index 2b9c91eb533b03b79d268f2027eca323265aa0f2..c6c470c390cb9f059b69b0e1d5ebf26113358e96 100644
--- a/src/effects/SkMorphologyImageFilter.cpp
+++ b/src/effects/SkMorphologyImageFilter.cpp
@@ -166,7 +166,7 @@ bool SkMorphologyImageFilter::filterImageGeneric(SkMorphologyImageFilter::Proc p
         return false;
     }
 
-    if (!dst->allocPixels(src.info().makeWH(bounds.width(), bounds.height()))) {
+    if (!dst->tryAllocPixels(src.info().makeWH(bounds.width(), bounds.height()))) {
         return false;
     }
 
@@ -191,7 +191,7 @@ bool SkMorphologyImageFilter::filterImageGeneric(SkMorphologyImageFilter::Proc p
     }
 
     SkBitmap temp;
-    if (!temp.allocPixels(dst->info())) {
+    if (!temp.tryAllocPixels(dst->info())) {
         return false;
     }