GCC 4.6 fix: intptr_t <-> NULL triggers an warning.

BUG=chromium:87001
TEST=none

Patch by Ryan Sleevi <rsleevi@chromium.org>
Review URL: http://codereview.appspot.com/4571048/

git-svn-id: http://skia.googlecode.com/svn/trunk@1538 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gpu/src/app-android.cpp b/gpu/src/app-android.cpp
index eea9a4d..e07aa1d 100644
--- a/gpu/src/app-android.cpp
+++ b/gpu/src/app-android.cpp
@@ -14,8 +14,8 @@
 
 static GrContext* make_context() {
     SkDebugf("---- before create\n");
-    GrContext* ctx = GrContext::Create(GrGpu::kOpenGL_Shaders_Engine, NULL);
-//    GrContext* ctx = GrContext::Create(GrGpu::kOpenGL_Fixed_Engine, NULL);
+    GrContext* ctx = GrContext::Create(GrGpu::kOpenGL_Shaders_Engine, 0);
+//    GrContext* ctx = GrContext::Create(GrGpu::kOpenGL_Fixed_Engine, 0);
     SkDebugf("---- after create %p\n", ctx);
     return ctx;
 }