Suppress int/NULL comparison warning



git-svn-id: http://skia.googlecode.com/svn/trunk@1275 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gpu/src/GrGpuFactory.cpp b/gpu/src/GrGpuFactory.cpp
index 642a55b..671ac47 100644
--- a/gpu/src/GrGpuFactory.cpp
+++ b/gpu/src/GrGpuFactory.cpp
@@ -53,7 +53,7 @@
 
     switch (engine) {
         case kOpenGL_Shaders_GrEngine:
-            GrAssert(NULL == context3D);
+            GrAssert(NULL == (void*)context3D);
             {
 #if 0 // old code path, will be removed soon
                 gpu = new GrGpuGLShaders2;
@@ -63,11 +63,11 @@
             }
             break;
         case kOpenGL_Fixed_GrEngine:
-            GrAssert(NULL == context3D);
+            GrAssert(NULL == (void*)context3D);
             gpu = new GrGpuGLFixed;
             break;
         case kDirect3D9_GrEngine:
-            GrAssert(NULL != context3D);
+            GrAssert(NULL != (void*)context3D);
 #if GR_WIN32_BUILD
 //            gpu = new GrGpuD3D9((IDirect3DDevice9*)context3D);
 #endif