Refactors and a potential public API for rendering

Split out the View/ViewRootImpl bits from the
hardware rendering bits.

Create a potential public API surface for
hardware rendering

Bug: 112709971
Test: builds & boots

Change-Id: I9e6f44b07a170574a905f42338282c4bb7e95f56
diff --git a/libs/hwui/renderthread/RenderThread.h b/libs/hwui/renderthread/RenderThread.h
index 62f704b..2384f95 100644
--- a/libs/hwui/renderthread/RenderThread.h
+++ b/libs/hwui/renderthread/RenderThread.h
@@ -74,7 +74,7 @@
     PREVENT_COPY_AND_ASSIGN(RenderThread);
 
 public:
-    // Sets a callback that fires before any RenderThread setup has occured.
+    // Sets a callback that fires before any RenderThread setup has occurred.
     ANDROID_API static void setOnStartHook(void (*onStartHook)());
 
     WorkQueue& queue() { return ThreadBase::queue(); }