Make SkImageGenerator::getPixels() return an enum.

src/lazy/SkCachingPixelRef.cpp

Index: src/lazy/SkCachingPixelRef.cpp
diff --git a/src/lazy/SkCachingPixelRef.cpp b/src/lazy/SkCachingPixelRef.cpp
index 5ab96562ec8184f9adb1671ea36ec1db54e31829..570fc6fbd78a5d75edc69d56a6bb85a673e4c375 100644
--- a/src/lazy/SkCachingPixelRef.cpp
+++ b/src/lazy/SkCachingPixelRef.cpp
@@ -52,9 +52,15 @@ bool SkCachingPixelRef::onNewLockPixels(LockRec* rec) {
             fErrorInDecoding = true;
             return false;
         }
-        if (!fImageGenerator->getPixels(info, fLockedBitmap.getPixels(), fRowBytes)) {
-            fErrorInDecoding = true;
-            return false;
+        const SkImageGenerator::Result result = fImageGenerator->getPixels(info,
+                fLockedBitmap.getPixels(), fRowBytes);
+        switch (result) {
+            case SkImageGenerator::kIncompleteInput:
+            case SkImageGenerator::kSuccess:
+                break;
+            default:
+                fErrorInDecoding = true;
+                return false;
         }
         fLockedBitmap.setImmutable();
         SkBitmapCache::Add(