Move part of metrics from chrome/common to components

components/metrics/README

Index: components/metrics/README
diff --git a/components/metrics/README b/components/metrics/README
new file mode 100644
index 0000000000000000000000000000000000000000..3461deaa96a370a70ec3d1341a04263b61434cb7
--- /dev/null
+++ b/components/metrics/README
@@ -0,0 +1,22 @@
+This component contains the base classes for the metrics service and only
+depends on //base. It is used by ChromeOS as the base for a standalone service
+that will upload the metrics when ChromeOS is not installed (headless install).
+
+This is the first step towards the componentization of metrics that will happen
+later this spring.
+
+A proposed structure for the metrics component is:
+//components/metrics/base,
+  Depends on base only. Contains the protobuf definitions.
+//components/metrics/core
+  Depends on everything iOS depends on
+//components/metrics/content
+  Depends on content
+
+Ideally, the component would abstract the network stack and have a clean
+separation between the metrics upload logic (protbuf generation, retry, etc...),
+the chrome part (gathering histogram from all the threads, populating the
+log with hardware characteristics, plugin state, etc.).
+
+It is a plus if the component stays in a single directory as it would be easier

[blundell, 2014/05/05 08:16:51]

nit: To avoid confusion, I would say "if the code currently in the component
(i.e., the code that can depend only on //base)" instead of "if the component".

+for ChromeOS to pull it :).