[headless] Embed pak file into binary.

ui/base/resource/data_pack.h

Index: ui/base/resource/data_pack.h
diff --git a/ui/base/resource/data_pack.h b/ui/base/resource/data_pack.h
index 46578186f23161a22b61e0924ad6a84d82d95c1b..9a2a35cf3cb6d2ee5f12009a99fb0802e8ada441 100644
--- a/ui/base/resource/data_pack.h
+++ b/ui/base/resource/data_pack.h
@@ -33,6 +33,8 @@ enum ScaleFactor : int;
 
 class UI_DATA_PACK_EXPORT DataPack : public ResourceHandle {
  public:
+  class DataSource;
+
   explicit DataPack(ui::ScaleFactor scale_factor);
   ~DataPack() override;
 
@@ -50,6 +52,9 @@ class UI_DATA_PACK_EXPORT DataPack : public ResourceHandle {
   bool LoadFromFileRegion(base::File file,
                           const base::MemoryMappedFile::Region& region);
 
+  // Loads a pack file from |buffer|, returning false on error.
+  bool LoadFromBuffer(base::StringPiece buffer);

[sky, 2016/05/19 20:25:54]

LoadFromStringPiece?
Also, I think it's worth mentioning life time. Specifically that this code does
*not* make a copy of the data.

[altimin, 2016/05/19 23:04:47]

I believe that LoadFromBuffer describes it more precisely, usage of StringPiece
for storing buffer is just an implementation detail.

Comment added.

+
   // Writes a pack file containing |resources| to |path|. If there are any
   // text resources to be written, their encoding must already agree to the
   // |textEncodingType| specified. If no text resources are present, please
@@ -75,11 +80,11 @@ class UI_DATA_PACK_EXPORT DataPack : public ResourceHandle {
 #endif
 
  private:
-  // Does the actual loading of a pack file. Called by Load and LoadFromFile.
+  // Does the actual loading of a pack file.
+  // Called by Load and LoadFromFile and LoadFromBuffer.
   bool LoadImpl();
 
-  // The memory-mapped data.
-  std::unique_ptr<base::MemoryMappedFile> mmap_;
+  std::unique_ptr<DataSource> data_source_;
 
   // Number of resources in the data.
   size_t resource_count_;