Consolidate SkCodec functions for handling rewind

Previously, many of our codec implementations followed the same
pattern (often in a function named handleRewind):

switch (this->rewindIfNeeded()) {
  case CouldNotRewind:
    return CouldNotRewind;
  case NoRewindNecessary:
    // keep going
    break;
  case Rewound:
     <re-read header etc>
    break;
}

In this CL, remove the enum, and put the piece that happens in the
Rewound case into a virtual function, onRewind. rewindIfNeeded now
contains the common pieces from various functions named handleRewind.

In SkBmpCodec, add a function that returns whether the BMP is in ICO,
so it can have a common implementation for onRewind.

BUG=skia:3257

Review URL: https://codereview.chromium.org/1288483002

1 files changed, 1 insertions, 1 deletions

diff --git a/src/codec/SkBmpRLECodec.cpp b/src/codec/SkBmpRLECodec.cpp
index 828871cd54..6be7449ed8 100644
--- a/src/codec/SkBmpRLECodec.cpp
+++ b/src/codec/SkBmpRLECodec.cpp
@@ -66,7 +66,7 @@ SkCodec::Result SkBmpRLECodec::onGetPixels(const SkImageInfo& dstInfo,
                                         const Options& opts,
                                         SkPMColor* inputColorPtr,
                                         int* inputColorCount) {
-    if (!this->handleRewind(false)) {
+    if (!this->rewindIfNeeded()) {
         return kCouldNotRewind;
     }
     if (opts.fSubset) {