Start cleaning up 64bit Win warnings

src/gpu/gl/GrGpuGL.cpp

Index: src/gpu/gl/GrGpuGL.cpp
===================================================================
--- src/gpu/gl/GrGpuGL.cpp	(revision 11758)
+++ src/gpu/gl/GrGpuGL.cpp	(working copy)
@@ -1149,7 +1149,7 @@
 
 ////////////////////////////////////////////////////////////////////////////////
 
-GrVertexBuffer* GrGpuGL::onCreateVertexBuffer(uint32_t size, bool dynamic) {
+GrVertexBuffer* GrGpuGL::onCreateVertexBuffer(size_t size, bool dynamic) {
     GrGLVertexBuffer::Desc desc;
     desc.fDynamic = dynamic;
     desc.fSizeInBytes = size;
@@ -1182,7 +1182,7 @@
     }
 }
 
-GrIndexBuffer* GrGpuGL::onCreateIndexBuffer(uint32_t size, bool dynamic) {
+GrIndexBuffer* GrGpuGL::onCreateIndexBuffer(size_t size, bool dynamic) {
     GrGLIndexBuffer::Desc desc;
     desc.fDynamic = dynamic;
     desc.fSizeInBytes = size;