Revert of Move gpu memory calculations to Compositor.

cc/output/context_provider.h

Index: cc/output/context_provider.h
diff --git a/cc/output/context_provider.h b/cc/output/context_provider.h
index db127064be2a59cb408705f95a90a70dd97641c7..cb13de9db1edef178a2c46057713d81f9fb2b39e 100644
--- a/cc/output/context_provider.h
+++ b/cc/output/context_provider.h
@@ -94,6 +94,13 @@ class ContextProvider : public base::RefCountedThreadSafe<ContextProvider> {
   virtual void SetLostContextCallback(
       const LostContextCallback& lost_context_callback) = 0;
 
+  // Sets a callback to be called when the memory policy changes. This should be
+  // called from the same thread that the context is bound to.
+  typedef base::Callback<void(const ManagedMemoryPolicy& policy)>
+      MemoryPolicyChangedCallback;
+  virtual void SetMemoryPolicyChangedCallback(
+      const MemoryPolicyChangedCallback& memory_policy_changed_callback) = 0;
+
  protected:
   friend class base::RefCountedThreadSafe<ContextProvider>;
   virtual ~ContextProvider() {}