change default impl to facilitate transition in blink/chrome

src/core/SkImageGenerator.cpp

Index: src/core/SkImageGenerator.cpp
diff --git a/src/core/SkImageGenerator.cpp b/src/core/SkImageGenerator.cpp
index 27bc141d577c4cb03a7b44c1dc278800e46500de..08c133d925aba4a24dcd2494c68bae9c2266da9e 100644
--- a/src/core/SkImageGenerator.cpp
+++ b/src/core/SkImageGenerator.cpp
@@ -123,8 +123,11 @@ SkData* SkImageGenerator::onRefEncodedData() {
 }
 
 #ifdef SK_SUPPORT_LEGACY_BOOL_ONGETINFO
-bool SkImageGenerator::onGetInfo(SkImageInfo*) {
-    return false;
+bool SkImageGenerator::onGetInfo(SkImageInfo* info) {
+    if (info) {
+        *info = fInfo;
+    }
+    return true;
 }
 #endif