Bug 1164027 - Use MAP_ANONYMOUS instead of opening /dev/zero. r=jrmuizel

MozReview-Commit-ID: 5GeNG5Tm1GS

--HG--
extra : histedit_source : 31e30d68fce2f97015c6e84da953e1b6f04fca50

gfx/gl/GLContext.cpp

@@ -12,7 +12,6 @@
 #include <ctype.h>
 #include <vector>
 #ifdef MOZ_WIDGET_ANDROID
-#include <fcntl.h>
 #include <sys/mman.h>
 #endif
 
@@ -2886,16 +2885,12 @@ WillTextureMapSucceed(GLsizei width, GLsizei height, GLenum format, GLenum type)
     // there to be double the actual size of the texture available.
     size_t size = width * height * GetBytesPerTexel(format, type) * 2;
 
-    int fd = open("/dev/zero", O_RDONLY);
-
-    void *p = mmap(nullptr, size, PROT_NONE, MAP_SHARED, fd, 0);
+    void *p = mmap(nullptr, size, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
     if (p != MAP_FAILED) {
         willSucceed = true;
         munmap(p, size);
     }
 
-    close(fd);
-
     return willSucceed;
 }
 #endif // MOZ_WIDGET_ANDROID