Initial version of Blimp BlobCache.

blimp/client/feature/compositor/decoding_image_generator.cc

Index: blimp/client/feature/compositor/decoding_image_generator.cc
diff --git a/blimp/client/feature/compositor/decoding_image_generator.cc b/blimp/client/feature/compositor/decoding_image_generator.cc
index 692dd373c4df152e1de69054ca0deef64b44f5bd..b05dfad01c48f3961b82a8c6618c3890ad19d97f 100644
--- a/blimp/client/feature/compositor/decoding_image_generator.cc
+++ b/blimp/client/feature/compositor/decoding_image_generator.cc
@@ -4,7 +4,9 @@
 
 #include "blimp/client/feature/compositor/decoding_image_generator.h"
 
+#include "base/numerics/safe_conversions.h"
 #include "blimp/common/compositor/webp_decoder.h"
+#include "blimp/common/proto/blob_cache.pb.h"
 #include "third_party/libwebp/webp/decode.h"
 #include "third_party/libwebp/webp/demux.h"
 #include "third_party/skia/include/core/SkData.h"
@@ -13,16 +15,20 @@ namespace blimp {
 namespace client {
 
 SkImageGenerator* DecodingImageGenerator::create(SkData* data) {
-  WebPData inputData = {reinterpret_cast<const uint8_t*>(data->data()),
-                        data->size()};
-  WebPDemuxState demuxState(WEBP_DEMUX_PARSING_HEADER);
-  WebPDemuxer* demux = WebPDemuxPartial(&inputData, &demuxState);
-
-  uint32_t width = WebPDemuxGetI(demux, WEBP_FF_CANVAS_WIDTH);
-  uint32_t height = WebPDemuxGetI(demux, WEBP_FF_CANVAS_HEIGHT);
+  std::unique_ptr<BlobCacheImageMetadata> parsed_metadata(

[vmpstr, 2016/04/15 18:18:54]

Since this seems to be only used locally, can you create this on the stack? That
is,

BlobCacheImageMetadata parsed_metadata;

[nyquist, 2016/04/16 00:25:29]

Done.

+      new BlobCacheImageMetadata);
+  int signed_size = base::checked_cast<int>(data->size());
+  if (!parsed_metadata->ParseFromArray(data->data(), signed_size)) {
+    // Failed to parse proto, so will fail to decode later as well. Inform
+    // Skia by giving back an empty SkImageInfo.
+    return new DecodingImageGenerator(SkImageInfo::MakeN32Premul(0, 0),
+                                      data->data(), data->size());
+  }
 
-  const SkImageInfo info = SkImageInfo::MakeN32Premul(width, height);
-  return new DecodingImageGenerator(info, data->data(), data->size());
+  return new DecodingImageGenerator(
+      SkImageInfo::MakeN32Premul(parsed_metadata->width(),
+                                 parsed_metadata->height()),
+      data->data(), data->size());
 }
 
 DecodingImageGenerator::DecodingImageGenerator(const SkImageInfo info,