Remove most ScopedVector usage from c/b/extensions.

extensions/browser/management_policy.cc

Index: extensions/browser/management_policy.cc
diff --git a/extensions/browser/management_policy.cc b/extensions/browser/management_policy.cc
index b09734a908b31b3b1c5c82a4555ed320544aa9d1..7128ba522aa5c09aa33ff018cc4d23f0baad008a 100644
--- a/extensions/browser/management_policy.cc
+++ b/extensions/browser/management_policy.cc
@@ -61,8 +61,10 @@ void ManagementPolicy::UnregisterProvider(Provider* provider) {
   providers_.erase(provider);
 }
 
-void ManagementPolicy::RegisterProviders(std::vector<Provider*> providers) {
-  providers_.insert(providers.begin(), providers.end());
+void ManagementPolicy::RegisterProviders(
+    const std::vector<std::unique_ptr<Provider>>& providers) {
+  for (const std::unique_ptr<Provider>& provider : providers)
+    providers_.insert(provider.get());

[asargent_no_longer_on_chrome, 2016/09/06 22:12:40]

Hmm, this is a little unusual - when I see unique_ptr's as arguments, I usually
expect ownership to be transferred (that's typically what happens with
single-argument unique_ptr's not wrapped in a vector). 

Doesn't it seem a little unsafe that we just hold on to raw ptr's here? Could
ownership be transferred? Or could we use weak_ptr or RefCounted? At a minimum
we should probably have some comment about the lifetime expectations. 

[lazyboy, 2016/09/06 23:49:38]

Ya.
I think this is what ScopedVector was kind of hiding:
ScopedVector<T>::get() returns raw pointers: vector<T*>, that what
RegisterProviders is called with.
Think so. I don't see an easy way to transfer ownership as multiple classes are
adding to |providers_| in different ways. SupervisedUserService would be one
hard one to fix.
I've added TODO in the header file beside |providers_|.
Could

 }
 
 bool ManagementPolicy::UserMayLoad(const Extension* extension,