Enable forced extension updates on NaCl arch mismatch.

extensions/common/extension.h

Index: extensions/common/extension.h
diff --git a/extensions/common/extension.h b/extensions/common/extension.h
index 668f52f6806af108db2709416e594fd601467675..378326f98cbd6b8b0ed65193ec8220bb8a3ad3b1 100644
--- a/extensions/common/extension.h
+++ b/extensions/common/extension.h
@@ -351,6 +351,14 @@ class Extension : public base::RefCountedThreadSafe<Extension> {
   void AddWebExtentPattern(const URLPattern& pattern);
   const URLPatternSet& web_extent() const { return extent_; }
 
+  // Updates the set of architectures for which this extension has platform-
+  // specific resources installed.
+  void SetPlatformSpecificResourceArchs(const std::set<std::string>& archs);

[Yoyo Zhou, 2014/09/04 02:14:23]

Does this really need to be stored on Extension? I don't think we should be
adding stuff like this in general to it. I think it'd be cleaner to have some
sort of PlatformSpecificArchChecker that the InstalledLoader and the downloader
both make use of. If that doesn't work, I think even InstalledLoader would be a
better place to store this data...

+
+  // Retrieves the set of architectures for which this extension has
+  // platform-specific resources installed.
+  void GetPlatformSpecificResourceArchs(std::set<std::string>* archs) const;
+
  private:
   friend class base::RefCountedThreadSafe<Extension>;
 
@@ -480,6 +488,10 @@ class Extension : public base::RefCountedThreadSafe<Extension> {
   // The flags that were passed to InitFromValue.
   int creation_flags_;
 
+  // The set of archs for which platform-specific resources are present in
+  // this extension installation. Null if these have not been identified yet.
+  std::set<std::string> platform_specific_resource_archs_;
+
   DISALLOW_COPY_AND_ASSIGN(Extension);
 };