Disable caching "Chrome Hotword Shared Module" extension (temporary).

chrome/browser/extensions/updater/extension_cache_impl.cc

Index: chrome/browser/extensions/updater/extension_cache_impl.cc
diff --git a/chrome/browser/extensions/updater/extension_cache_impl.cc b/chrome/browser/extensions/updater/extension_cache_impl.cc
index a6300b8214294a8e46b9c1a1d1160a81b718f698..5c679f60ee034c075f5432376b6a3558d95e2f19 100644
--- a/chrome/browser/extensions/updater/extension_cache_impl.cc
+++ b/chrome/browser/extensions/updater/extension_cache_impl.cc
@@ -21,6 +21,10 @@
 namespace extensions {
 namespace {
 
+// Temporary workaround for M41, this extension should not be cached.
+// TODO: Implement id/hash-based map instead of id/version.

[Dmitry Polukhin, 2015/01/15 09:40:38]

Please use TODO(ginkage)... as in style guide and move it to AllowCaching.

+const char kBlacklistedExt[] = "lccekmodgklaepjeofjdjpbminllajkg";

[Dmitry Polukhin, 2015/01/15 09:40:38]

This constant already exists kHotwordSharedModuleId please use it instead.

+
 #if defined(OS_CHROMEOS)
 const char kLocalCacheDir[] = "/var/cache/external_cache";
 #else
@@ -72,13 +76,15 @@ void ExtensionCacheImpl::Shutdown(const base::Closure& callback) {
 }
 
 void ExtensionCacheImpl::AllowCaching(const std::string& id) {
+  if (id == kBlacklistedExt)
+    return;
   allowed_extensions_.insert(id);
 }
 
 bool ExtensionCacheImpl::GetExtension(const std::string& id,
                                       base::FilePath* file_path,
                                       std::string* version) {
-  if (cache_)
+  if (cache_ && id != kBlacklistedExt)

[Dmitry Polukhin, 2015/01/15 09:40:38]

I would check if caching allowed like this 'ContainsKey(allowed_extensions_,
id)' or even make this check separate function to call it from PutExtension and
GetExtension.

[ginkage, 2015/01/15 15:02:24]

I'm not really sure: I've added this check for cases when the extension is
already in the cache, but we should not use it (like, after a system upgrade).
Otherwise, AllowCaching check is sufficient.

[Dmitry Polukhin, 2015/01/15 15:07:48]

Yes, check in GetExtension required to recover if wrong variant is already in
the cache. Repeating check in GetExtension should generalize cases like when
extension shouldn't be cache and used from cache in any case.

     return cache_->GetExtension(id, file_path, version);
   else
     return false;