Make drawIndexedInstances non-virtual and rewrite GrIODB's drawRect on top of drawIndexedInstances.

R=robertphillips@google.com
Review URL: https://codereview.appspot.com/7221078

git-svn-id: http://skia.googlecode.com/svn/trunk@7508 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gyp/SampleApp.gyp b/gyp/SampleApp.gyp
index d635535..8d833dd 100644
--- a/gyp/SampleApp.gyp
+++ b/gyp/SampleApp.gyp
@@ -67,6 +67,7 @@
         '../samplecode/SampleLayers.cpp',
         '../samplecode/SampleLCD.cpp',
         '../samplecode/SampleLines.cpp',
+        '../samplecode/SampleManyRects.cpp',
         '../samplecode/SampleMeasure.cpp',
         '../samplecode/SampleMipMap.cpp',
         '../samplecode/SampleMovie.cpp',