Fixed mingw compilation.

Change-Id: I8ae33c752feb19e291e4a3b128d21a0ced883c90
Reviewed-on: https://chromium-review.googlesource.com/220761
Reviewed-by: Shannon Woods <shannonwoods@chromium.org>
Tested-by: Shannon Woods <shannonwoods@chromium.org>
diff --git a/src/libGLESv2/validationES.cpp b/src/libGLESv2/validationES.cpp
index 1b6180d..38c8c5e 100644
--- a/src/libGLESv2/validationES.cpp
+++ b/src/libGLESv2/validationES.cpp
@@ -1667,7 +1667,7 @@
     // TODO: also disable index checking on back-ends that are robust to out-of-range accesses.
     if (elementArrayBuffer)
     {
-        unsigned int offset = reinterpret_cast<unsigned int>(indices);
+        uintptr_t offset = reinterpret_cast<uintptr_t>(indices);
         if (!elementArrayBuffer->getIndexRangeCache()->findRange(type, offset, count, indexRangeOut, NULL))
         {
             const void *dataPointer = elementArrayBuffer->getImplementation()->getData();