[image_decode_bench] Remove use of SharedBuffer::Data()

SharedBuffer::Data() is deprecated, and was being used to consolidate
the buffer into one contiguous piece of memory. This is now redundant
since the ShardBuffer is created in ReadFile() by adopting the Vector
of image data (which is a contiguous piece of memory under the hood).

Remove the SharedBuffer::Data() call, move the related error handling
for ReadFile() back into that routine.

Bug: 601198
Change-Id: Ic0eab97ead78a967180d1ee6bdcb708e3cc3a4e5
Reviewed-on: https://chromium-review.googlesource.com/956644Reviewed-by: Leon Scroggins <scroggo@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#542102}

third_party/WebKit/Source/platform/testing/ImageDecodeBench.cpp

@@ -40,11 +40,13 @@ scoped_refptr<SharedBuffer> ReadFile(const char* name) {
   }
 
   file.seekg(0, std::ios::end);
-  size_t file_size = file.tellg();
+  int file_size = file.tellg();
   file.seekg(0, std::ios::beg);
 
-  if (!file || !file_size)
-    return SharedBuffer::Create();
+  if (!file || file_size <= 0) {
+    fprintf(stderr, "Error seeking file %s\n", name);
+    exit(2);
+  }
 
   Vector<char> buffer(file_size);
   if (!file.read(buffer.data(), file_size)) {
@@ -126,21 +128,11 @@ int ImageDecodeBenchMain(int argc, char* argv[]) {
   class WebPlatform : public Platform {};
   Platform::Initialize(new WebPlatform());
 
-  // Read entire file content to data, and consolidate the SharedBuffer data
-  // segments into one, contiguous block of memory.
+  // Read entire file content into |data| (a contiguous block of memory) then
+  // decode it to verify the image and record its ImageMeta data.
 
+  ImageMeta image = {argv[1], 0, 0, 0, 0};
   scoped_refptr<SharedBuffer> data = ReadFile(argv[1]);
-  if (!data.get() || !data->size()) {
-    fprintf(stderr, "Error reading image %s\n", argv[1]);
-    exit(2);
-  }
-
-  data->Data();
-
-  // Warm-up: throw out the first iteration for more consistent results.
-
-  ImageMeta image;
-  image.name = argv[1];
   DecodeImageData(data.get(), &image);
 
   // Image decode bench for decode_iterations.