Consolidate SkCodec functions for handling rewind

src/codec/SkCodec_wbmp.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCodec.h"
 #include "SkCodecPriv.h"
 #include "SkColorPriv.h"
@@ skipping 48 matching lines @@
     }
     if (!read_mbf(stream, &height) || height > 0xFFFF || !height) {
         return false;
     }
     if (size) {
         *size = SkISize::Make(SkToS32(width), SkToS32(height));
     }
     return true;
 }
 
-bool SkWbmpCodec::handleRewind() {
-    SkCodec::RewindState rewindState = this->rewindIfNeeded();
-    if (rewindState == kCouldNotRewind_RewindState) {
-        return false;
-    } else if (rewindState == kRewound_RewindState) {
-        if (!read_header(this->stream(), NULL)) {
-            return false;
-        }
-    }
-    return true;
+bool SkWbmpCodec::onRewind() {
+    return read_header(this->stream(), NULL);
 }
 
 SkSwizzler* SkWbmpCodec::initializeSwizzler(const SkImageInfo& info,
         const SkPMColor* ctable, const Options& opts) {
     // TODO (msarett): Reenable support for 565 if it is desired
     //                 skbug.com/3683
 
     // Create the swizzler based on the desired color type
     switch (info.colorType()) {
         case kIndex_8_SkColorType:
@@ skipping 21 matching lines @@
 SkEncodedFormat SkWbmpCodec::onGetEncodedFormat() const {
     return kWBMP_SkEncodedFormat;
 }
 
 SkCodec::Result SkWbmpCodec::onGetPixels(const SkImageInfo& info,
                                          void* dst,
                                          size_t rowBytes,
                                          const Options& options,
                                          SkPMColor ctable[],
                                          int* ctableCount) {
-    if (!this->handleRewind()) {
+    if (!this->rewindIfNeeded()) {
         return kCouldNotRewind;
     }
     if (options.fSubset) {
         // Subsets are not supported.
         return kUnimplemented;
     }
     if (info.dimensions() != this->getInfo().dimensions()) {
         return kInvalidScale;
     }
 
@@ skipping 59 matching lines @@
             }
             fSwizzler->swizzle(dstRow, fSrcBuffer.get());
             dstRow = SkTAddOffset<void>(dstRow, dstRowBytes);
         }
         return SkCodec::kSuccess;
     }
 
     SkCodec::Result onStart(const SkImageInfo& dstInfo,
             const SkCodec::Options& options, SkPMColor inputColorTable[],
             int* inputColorCount) {
-        if (!fCodec->handleRewind()) {
+        if (!fCodec->rewindIfNeeded()) {
             return SkCodec::kCouldNotRewind;
         }
         if (options.fSubset) {
             // Subsets are not supported.
             return SkCodec::kUnimplemented;
         }
         if (dstInfo.dimensions() != this->getInfo().dimensions()) {
             return SkCodec::kInvalidScale;
         }
 
@@ skipping 27 matching lines @@
 SkScanlineDecoder* SkWbmpCodec::NewSDFromStream(SkStream* stream) {
     SkAutoTDelete<SkWbmpCodec> codec(static_cast<SkWbmpCodec*>(
             SkWbmpCodec::NewFromStream(stream)));
     if (!codec) {
         return NULL;
     }
 
     // Return the new scanline decoder
     return SkNEW_ARGS(SkWbmpScanlineDecoder, (codec.detach()));
 }