Compressing .pak resources with new option: "type=GZIPPABLE_BINDATA"

ui/base/resource/resource_bundle.h

Index: ui/base/resource/resource_bundle.h
diff --git a/ui/base/resource/resource_bundle.h b/ui/base/resource/resource_bundle.h
index f58b1269fc8c9f2e3e18f786dff23ab19b5e28ac..dc5f8eb727e75fc2c1f0bb2984d0400a77d0262b 100644
--- a/ui/base/resource/resource_bundle.h
+++ b/ui/base/resource/resource_bundle.h
@@ -50,6 +50,8 @@ class UI_BASE_EXPORT ResourceBundle {
   static const int kMediumFontDelta = 3;
   static const int kLargeFontDelta = 8;
 
+  static constexpr const char* CUSTOM_GZIP_HEADER = "\xff\x1f\x8b";
+
   // Legacy font style mappings. TODO(tapted): Phase these out in favour of
   // client code providing their own constant with the desired font size delta.
   enum FontStyle {
@@ -216,25 +218,35 @@ class UI_BASE_EXPORT ResourceBundle {
   gfx::Image& GetNativeImageNamed(int resource_id);
 
   // Loads the raw bytes of a scale independent data resource.
+  // Will perform gzip decompression on any resource which has
+  // ResourceBundle::CUSTOM_GZIP_HEADER as its first 3 bytes.
+  // To compress a resource, add 'compress="gzip"' to that resource's .grd file.
   base::RefCountedMemory* LoadDataResourceBytes(int resource_id) const;
 
   // Loads the raw bytes of a data resource nearest the scale factor
   // |scale_factor| into |bytes|, without doing any processing or
   // interpretation of the resource. Use ResourceHandle::SCALE_FACTOR_NONE
   // for scale independent image resources (such as wallpaper).
+  // Will perform gzip decompression on any resource which has
+  // ResourceBundle::CUSTOM_GZIP_HEADER as its first 3 bytes.
+  // To compress a resource, add 'compress="gzip"' to that resource's .grd file.
   // Returns NULL if we fail to read the resource.
   base::RefCountedMemory* LoadDataResourceBytesForScale(
       int resource_id,
       ScaleFactor scale_factor) const;
 
   // Return the contents of a scale independent resource in a
-  // StringPiece given the resource id
+  // StringPiece given the resource id.
+  // NOTE: CHECKs to ensure this is not called on a resource which has
+  // ResourceBundle::CUSTOM_GZIP_HEADER as its first 3 bytes.
   base::StringPiece GetRawDataResource(int resource_id) const;
 
   // Return the contents of a resource in a StringPiece given the resource id
   // nearest the scale factor |scale_factor|.
   // Use ResourceHandle::SCALE_FACTOR_NONE for scale independent image resources
   // (such as wallpaper).
+  // NOTE: CHECKs to ensure this is not called on a resource which has
+  // ResourceBundle::CUSTOM_GZIP_HEADER as its first 3 bytes.
   base::StringPiece GetRawDataResourceForScale(int resource_id,
                                                ScaleFactor scale_factor) const;
 
@@ -382,6 +394,15 @@ class UI_BASE_EXPORT ResourceBundle {
                   SkBitmap* bitmap,
                   bool* fell_back_to_1x) const;
 
+  // Loads the raw bytes of a data resource nearest the scale factor
+  // |scale_factor| into |bytes|, without doing any processing or
+  // interpretation of the resource. Use ResourceHandle::SCALE_FACTOR_NONE
+  // for scale independent image resources (such as wallpaper).
+  // Returns NULL if we fail to read the resource.
+  base::StringPiece DoGetRawDataResourceForScale(
+      int resource_id,
+      ScaleFactor scale_factor) const;
+
   // Returns true if missing scaled resources should be visually indicated when
   // drawing the fallback (e.g., by tinting the image).
   static bool ShouldHighlightMissingScaledResources();