SkScaledCodec class

This class does scaling by using a scanlineDecoder.
getScanlines and skipScanlines are used for y sampling,
the swizzler is used for x sampling

this class is currently only working for png and jpeg images
I will update other Codec types to work soon

For SkJpegCodec to implement width wise swizzling it now
uses a swizzler. I ran performance tests on this change.
Here are the performance test results:
https://docs.google.com/a/google.com/spreadsheets/d/1D7-Q_GXD_dI68LZO005NNvb8Wq2Ee0wEBEPG72671yw/edit?usp=sharing

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/0944100ac89f797714eeae0cf2875e2335ff52ee

Committed: https://skia.googlesource.com/skia/+/d518ea7927f9f4e0ed5b4134d1b4f48243855a47

Committed: https://skia.googlesource.com/skia/+/b157917507d4f7d2651f0aeb566d31603cc02240

Review URL: https://codereview.chromium.org/1260673002

1 files changed, 11 insertions, 4 deletions

diff --git a/src/codec/SkCodec_wbmp.cpp b/src/codec/SkCodec_wbmp.cpp
index 6f98294fc6..3081a3bba9 100644
--- a/src/codec/SkCodec_wbmp.cpp
+++ b/src/codec/SkCodec_wbmp.cpp
@@ -9,6 +9,7 @@
 #include "SkCodecPriv.h"
 #include "SkColorPriv.h"
 #include "SkColorTable.h"
+#include "SkScaledCodec.h"
 #include "SkStream.h"
 #include "SkCodec_wbmp.h"
 
@@ -80,8 +81,8 @@ SkSwizzler* SkWbmpCodec::initializeSwizzler(const SkImageInfo& info,
         case kIndex_8_SkColorType:
         case kN32_SkColorType:
         case kGray_8_SkColorType:
-            return SkSwizzler::CreateSwizzler(
-                    SkSwizzler::kBit, ctable, info, opts.fZeroInitialized);
+            return SkSwizzler::CreateSwizzler(SkSwizzler::kBit, ctable, info, opts.fZeroInitialized, 
+                                              this->getInfo());
         default:
             return NULL;
     }
@@ -201,7 +202,9 @@ public:
             return SkCodec::kUnimplemented;
         }
         if (dstInfo.dimensions() != this->getInfo().dimensions()) {
-            return SkCodec::kInvalidScale;
+            if (!SkScaledCodec::DimensionsSupportedForSampling(this->getInfo(), dstInfo)) {
+                return SkCodec::kInvalidScale;
+            }
         }
 
         if (!valid_alpha(dstInfo.alphaType(), this->getInfo().alphaType())) {
@@ -220,12 +223,16 @@ public:
         fSwizzler.reset(fCodec->initializeSwizzler(dstInfo,
                 get_color_ptr(fColorTable.get()), options));
         if (NULL == fSwizzler.get()) {
-            return SkCodec::kInvalidInput;
+            return SkCodec::kInvalidConversion;
         }
 
         return SkCodec::kSuccess;
     }
 
+    SkEncodedFormat onGetEncodedFormat() const {
+        return kWBMP_SkEncodedFormat;
+    }
+
 private:
     SkAutoTDelete<SkWbmpCodec>   fCodec;
     SkAutoTUnref<SkColorTable>   fColorTable;