Isolate GrBufferAllocPools inside GrBatchTarget

This CL refactors the location of the GrBufferAllocPools so they reside entirely inside the GrBatchTarget. This is in preparation for making them use scratch resources.

Review URL: https://codereview.chromium.org/1131553002
diff --git a/src/gpu/GrTest.cpp b/src/gpu/GrTest.cpp
index dfec048..727fbbc 100644
--- a/src/gpu/GrTest.cpp
+++ b/src/gpu/GrTest.cpp
@@ -131,7 +131,6 @@
 // Code for the mock context. It's built on a mock GrGpu class that does nothing.
 ////
 
-#include "GrBufferAllocPool.h"
 #include "GrInOrderDrawBuffer.h"
 #include "GrGpu.h"
 
@@ -266,10 +265,6 @@
     // these objects are required for any of tests that use this context. TODO: make stop allocating
     // resources in the buffer pools.
     SkDELETE(fDrawBuffer);
-    SkDELETE(fDrawBufferVBAllocPool);
-    SkDELETE(fDrawBufferIBAllocPool);
-
     fDrawBuffer = NULL;
-    fDrawBufferVBAllocPool = NULL;
-    fDrawBufferIBAllocPool = NULL;
+
 }