rename GrDrawTargetCaps.h to GrCaps.h and move to include

Review URL: https://codereview.chromium.org/1135113005
diff --git a/src/gpu/GrGpu.cpp b/src/gpu/GrGpu.cpp
index b7d362c..7fc1491 100644
--- a/src/gpu/GrGpu.cpp
+++ b/src/gpu/GrGpu.cpp
@@ -9,8 +9,8 @@
 
 #include "GrGpu.h"
 
+#include "GrCaps.h"
 #include "GrContext.h"
-#include "GrDrawTargetCaps.h"
 #include "GrGpuResourcePriv.h"
 #include "GrIndexBuffer.h"
 #include "GrResourceCache.h"