Delegating the "are images allowed" decision to renderer.

chrome/common/render_messages.h

Index: chrome/common/render_messages.h
diff --git a/chrome/common/render_messages.h b/chrome/common/render_messages.h
index 7e09b6e5850b7cace20cfca8af3d54bb683871e2..cf939e4213fe79f503acafb561f53dfeae61ecc0 100644
--- a/chrome/common/render_messages.h
+++ b/chrome/common/render_messages.h
@@ -19,6 +19,8 @@
 #include "base/values.h"
 #include "build/build_config.h"
 #include "chrome/common/common_param_traits.h"
+#include "chrome/common/content_settings.h"
+#include "chrome/common/content_settings_pattern.h"
 #include "chrome/common/instant_types.h"
 #include "chrome/common/nacl_types.h"
 #include "chrome/common/search_provider.h"
@@ -102,6 +104,14 @@ struct ParamTraits<ContentSettings> {
   static void Log(const param_type& p, std::string* l);
 };
 
+template <>
+struct ParamTraits<ContentSettingsPattern> {

[Bernhard Bauer, 2011/10/17 13:13:19]

I think you could do this via the |IPC_STRUCT_TRAITS_| macros like below
(directly serializing the parts of the parsed pattern instead of stringifying
and re-parsing it). 

[marja, 2011/10/18 12:23:02]

Done. But, I had to make ContentSettingsPattern::PatternParts, parts_ and
is_valid_ public, to be able to do this. Is that ok? It also exposes the
internal structure of ContentSettingsPattern, whereas the previous solution
assumed that they can be converted to strings and back without losing
information. Not sure which is more elegant.

[Bernhard Bauer, 2011/10/18 13:14:31]

Making ContentSettingsPattern::PatternParts itself public is fine. |parts_| and
|is_valid_| shouldn't be public. I mainly want to use the macros for
ContentSettingsPattern::PatternParts (to avoid repetition), so you could declare
ParamTraits<ContentSettingsPattern> here and then serialize the PatternParts in
the implementation (declaring IPC::ParamTraits<ContentSettingsPattern> a
friend)?

[marja, 2011/10/19 16:56:35]

(This got resolved by your CL.)

+  typedef ContentSettingsPattern param_type;
+  static void Write(Message* m, const param_type& p);
+  static bool Read(const Message* m, void** iter, param_type* r);
+  static void Log(const param_type& p, std::string* l);
+};
+
 }  // namespace IPC
 
 #endif  // CHROME_COMMON_RENDER_MESSAGES_H_
@@ -216,6 +226,10 @@ IPC_MESSAGE_CONTROL2(ChromeViewMsg_SetContentSettingsForCurrentURL,
 IPC_MESSAGE_CONTROL1(ChromeViewMsg_SetDefaultContentSettings,
                      ContentSettings /* content_settings */)
 
+// Set the content settings for images.
+IPC_MESSAGE_CONTROL1(ChromeViewMsg_SetImageSettingRules,
+                     ContentSettingsForOneType /* rules */)
+
 // Tells the render view to load all blocked plugins.
 IPC_MESSAGE_ROUTED0(ChromeViewMsg_LoadBlockedPlugins)