Add new ResourceBundle::Delegate interface.

ui/base/resource/resource_bundle.h

Index: ui/base/resource/resource_bundle.h
===================================================================
--- ui/base/resource/resource_bundle.h	(revision 134688)
+++ ui/base/resource/resource_bundle.h	(working copy)
@@ -19,6 +19,8 @@
 #include "base/string16.h"
 #include "base/string_piece.h"
 #include "ui/base/ui_export.h"
+#include "ui/gfx/font.h"
+#include "ui/gfx/image/image.h"
 #include "ui/gfx/native_widget_types.h"
 
 class SkBitmap;
@@ -28,11 +30,6 @@
 class RefCountedStaticMemory;
 }
 
-namespace gfx {
-class Font;
-class Image;
-}
-
 namespace ui {
 
 class ResourceHandle;
@@ -63,12 +60,60 @@
     RTL_DISABLED,
   };
 
-  // Initialize the ResourceBundle for this process.  Returns the language
-  // selected.
+  class Delegate {

[tony, 2012/05/02 20:41:20]

Are delegates expected to deal with thread safety on their own?  In Chrome, we
allow calls to load resources/strings from any thread.  I'm not sure if this is
an issue for content_shell or ash.

[Marshall, 2012/05/03 19:10:54]

Yes, the delegate will need to deal with thread safety issues. I've added a
comment in the head to that effect.

+   public:
+    // Retrieve the full path for the specified |pack_name|. |pack_path| will
+    // initially contain the default path for the pack file. Change it in this
+    // callback if a different path is desired. Return true to continue loading
+    // the pack file or false to cancel the load.
+    virtual bool GetPathForResourcePack(const std::string& pack_name,
+                                        FilePath* pack_path,
+                                        float scale_factor) = 0;

[tony, 2012/05/02 20:41:20]

I would keep pack_name as a FilePath.  What if we wanted to load a pack_name
with non-ascii in it? Out parameters (pack_path) should come last.

[Marshall, 2012/05/03 19:10:54]

Done.

+
+    // Retrieve the full path for the specified |locale|. |pack_path| will
+    // initially contain the default path for the pack file. Change it in this
+    // callback if a different path is desired. Return true to continue loading
+    // the pack file or false to cancel the load.
+    virtual bool GetPathForLocalePack(const std::string& locale,
+                                      FilePath* pack_path) = 0;

[tony, 2012/05/02 20:41:20]

I would just return a FilePath (empty to cancel the load).  If the delegate
doesn't want to change it, it returns the pack_path passed in.

Maybe you would do the same with GetPathForResourcePack, but it's a bit
different since the "do nothing" case means appending pack_name to pack_path.

[Marshall, 2012/05/03 19:10:54]

Done.

+
+    // Return an image resource or NULL to attempt retrieval of the default
+    // resource.
+    virtual scoped_ptr<gfx::Image> GetImageNamed(int resource_id) = 0;
+
+    // Return an image resource or NULL to attempt retrieval of the default
+    // resource.
+    virtual scoped_ptr<gfx::Image> GetNativeImageNamed(int resource_id,
+                                                       ImageRTL rtl) = 0;
+
+    // Return a static memory resource or NULL to attempt retrieval of the
+    // default resource.
+    virtual base::RefCountedStaticMemory* LoadDataResourceBytes(
+        int resource_id) = 0;
+
+    // Retrieve a raw data resource. Return true if a resource was provided or
+    // false to attempt retrieval of the default resource.
+    virtual bool GetRawDataResource(int resource_id,
+                                    base::StringPiece* value) = 0;
+
+    // Retrieve a localized string. Return true if a string was provided or
+    // false to attempt retrieval of the default string.
+    virtual bool GetLocalizedString(int message_id, string16* value) = 0;
+
+    // Return a font resource or NULL to attempt retrieval of the default
+    // resource.
+    virtual scoped_ptr<gfx::Font> GetFont(FontStyle style) = 0;
+
+   protected:
+    virtual ~Delegate() {}
+  };
+
+  // Initialize the ResourceBundle for this process. Does not take ownership of
+  // the |delegate| value. Returns the language selected.
   // NOTE: Mac ignores this and always loads up resources for the language
   // defined by the Cocoa UI (i.e., NSBundle does the language work).
   static std::string InitSharedInstanceWithLocale(
-      const std::string& pref_locale);
+      const std::string& pref_locale, Delegate* delegate);
 
   // Initialize the ResourceBundle using given data pack path for testing.
   static void InitSharedInstanceWithPakFile(const FilePath& path);
@@ -83,14 +128,18 @@
   static ResourceBundle& GetSharedInstance();
 
   // Check if the .pak for the given locale exists.
-  static bool LocaleDataPakExists(const std::string& locale);
+  bool LocaleDataPakExists(const std::string& locale);

[tony, 2012/05/02 20:41:20]

Does this need to be public?

[Marshall, 2012/05/03 19:10:54]

It's used by l10n_util.cc currently.

 
-  // Registers additional data pack files with the global ResourceBundle.  When
-  // looking for a DataResource, we will search these files after searching the
-  // main module. |scale_factor| is the scale of images in this resource pak
-  // relative to the images in the 1x resource pak. This method is not thread
-  // safe! You should call it immediately after calling InitSharedInstance.
-  void AddDataPack(const FilePath& path, float scale_factor);
+  // Registers additional data pack files with the ResourceBundle.  When looking
+  // for a DataResource, we will search these files after searching the main
+  // module. |pack_name| is the name of the pack file (minus the extension)
+  // that will be passed to the delegate. |scale_factor| is the scale of images
+  // in this resource pak relative to the images in the 1x resource pak. This
+  // method is not thread safe! You should call it immediately after calling
+  // InitSharedInstance.
+  void AddDataPack(const std::string& pack_name,

[tony, 2012/05/02 20:41:20]

I would leave this interface unchanged and and split the path into filename and
directory pieces in the function itself.  Should be less code churn.

[Marshall, 2012/05/03 19:10:54]

Done.

+                   const FilePath& path,
+                   float scale_factor);
 
   // Changes the locale for an already-initialized ResourceBundle, returning the
   // name of the newly-loaded locale.  Future calls to get strings will return
@@ -149,10 +198,19 @@
   void OverrideLocalePakForTest(const FilePath& pak_path);
 
  private:
+  FRIEND_TEST_ALL_PREFIXES(ResourceBundle, DelegateGetPathForResourcePack);
+  FRIEND_TEST_ALL_PREFIXES(ResourceBundle, DelegateGetPathForLocalePack);
+  FRIEND_TEST_ALL_PREFIXES(ResourceBundle, DelegateGetImageNamed);
+  FRIEND_TEST_ALL_PREFIXES(ResourceBundle, DelegateGetNativeImageNamed);
+  FRIEND_TEST_ALL_PREFIXES(ResourceBundle, DelegateLoadDataResourceBytes);
+  FRIEND_TEST_ALL_PREFIXES(ResourceBundle, DelegateGetRawDataResource);
+  FRIEND_TEST_ALL_PREFIXES(ResourceBundle, DelegateGetLocalizedString);
+  FRIEND_TEST_ALL_PREFIXES(ResourceBundle, DelegateGetFont);
   FRIEND_TEST_ALL_PREFIXES(ResourceBundle, LoadDataResourceBytes);
+  FRIEND_TEST_ALL_PREFIXES(ResourceBundle, LocaleDataPakExists);
 
   // Ctor/dtor are private, since we're a singleton.
-  ResourceBundle();
+  explicit ResourceBundle(Delegate* delegate);
   ~ResourceBundle();
 
   // Free skia_images_.
@@ -177,7 +235,7 @@
 
   // Returns the full pathname of the locale file to load.  May return an empty
   // string if no locale data files are found.
-  static FilePath GetLocaleFilePath(const std::string& app_locale);
+  FilePath GetLocaleFilePath(const std::string& app_locale);
 
   // Creates and returns a new SkBitmap given the data file to look in and the
   // resource id.  It's up to the caller to free the returned bitmap when
@@ -190,6 +248,9 @@
 
   const FilePath& GetOverriddenPakPath();
 
+  // This pointer is guaranteed to outlive the ResourceBundle instance.

[tony, 2012/05/02 20:41:20]

I would add that it can be NULL.

[Marshall, 2012/05/03 19:10:54]

Done.

+  Delegate* delegate_;
+
   // Protects |images_| and font-related members.
   scoped_ptr<base::Lock> images_and_fonts_lock_;