Avoid initializing memory twice on incomplete RLE bmps

BUG=skia:4582
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1689983002

Review URL: https://codereview.chromium.org/1689983002

1 files changed, 7 insertions, 2 deletions

diff --git a/src/codec/SkBmpRLECodec.cpp b/src/codec/SkBmpRLECodec.cpp
index 57707d60c9..05691cc079 100644
--- a/src/codec/SkBmpRLECodec.cpp
+++ b/src/codec/SkBmpRLECodec.cpp
@@ -520,8 +520,13 @@ private:
     SkBmpRLECodec* fCodec;
 };
 
-SkSampler* SkBmpRLECodec::getSampler(bool createIfNecessary) {
-    if (!fSampler && createIfNecessary) {
+SkSampler* SkBmpRLECodec::getSampler(bool /*createIfNecessary*/) {
+    // We will always create an SkBmpRLESampler if one is requested.
+    // This allows clients to always use the SkBmpRLESampler's
+    // version of fill(), which does nothing since RLE decodes have
+    // already filled pixel memory.  This seems fine, since creating
+    // an SkBmpRLESampler is pretty inexpensive.
+    if (!fSampler) {
         fSampler.reset(new SkBmpRLESampler(this));
     }