Add a class to replace ImageLoadingTracker with a nicer API.

chrome/browser/extensions/extension_install_prompt.h

Index: chrome/browser/extensions/extension_install_prompt.h
diff --git a/chrome/browser/extensions/extension_install_prompt.h b/chrome/browser/extensions/extension_install_prompt.h
index 1b65fa66e69dde2441baf2f9a487630102c3a587..03beaae292bc47476f745fc11bfecd60f91cfb1f 100644
--- a/chrome/browser/extensions/extension_install_prompt.h
+++ b/chrome/browser/extensions/extension_install_prompt.h
@@ -12,7 +12,6 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/string16.h"
 #include "chrome/browser/extensions/crx_installer_error.h"
-#include "chrome/browser/extensions/image_loading_tracker.h"
 #include "chrome/common/extensions/url_pattern.h"
 #include "google_apis/gaia/oauth2_mint_token_flow.h"
 #include "third_party/skia/include/core/SkBitmap.h"
@@ -42,8 +41,8 @@ class PermissionSet;
 }  // namespace extensions
 
 // Displays all the UI around extension installation.
-class ExtensionInstallPrompt : public ImageLoadingTracker::Observer,
-                               public OAuth2MintTokenFlow::Delegate {
+class ExtensionInstallPrompt : public OAuth2MintTokenFlow::Delegate,
+    public base::SupportsWeakPtr<ExtensionInstallPrompt> {

[Finnur, 2012/10/05 14:41:33]

If the second doesn't fit within 80 cols when aligned with the other public,
then I'd move the first public down one line so you can align them.

[Marijn Kruisselbrink, 2012/10/05 18:00:08]

Done.

  public:
   enum PromptType {
     UNSET_PROMPT_TYPE = -1,
@@ -240,10 +239,8 @@ class ExtensionInstallPrompt : public ImageLoadingTracker::Observer,
   // Installation failed. This is declared virtual for testing.
   virtual void OnInstallFailure(const extensions::CrxInstallerError& error);
 
-  // ImageLoadingTracker::Observer:
-  virtual void OnImageLoaded(const gfx::Image& image,
-                             const std::string& extension_id,
-                             int index) OVERRIDE;
+  // extension_image_utils callback.
+  void OnImageLoaded(const gfx::Image& image);

[Finnur, 2012/10/05 14:41:33]

Is there a reason to keep these public? Can you not bind against them if they
are private? I think the only reason they were public was because of an old
Chrome team rule: one shouldn't change the visibility of functions while
overriding them (inheriting a public function, the override should be public).

[Aaron Boodman, 2012/10/05 16:46:03]

I did not know about that rule. I very frequently do the opposite.

[Marijn Kruisselbrink, 2012/10/05 18:00:08]

Done.

 
  protected:
   friend class extensions::ExtensionWebstorePrivateApiTest;
@@ -307,10 +304,6 @@ class ExtensionInstallPrompt : public ImageLoadingTracker::Observer,
   PromptType prompt_type_;
 
   scoped_ptr<OAuth2MintTokenFlow> token_flow_;
-
-  // Keeps track of extension images being loaded on the File thread for the
-  // purpose of showing the install UI.
-  ImageLoadingTracker tracker_;
 };
 
 namespace chrome {