Ashmem functions compile when size_t != __u32

R=djsollen@google.com, scroggo@google.com

Author: halcanary@google.com

Review URL: https://codereview.chromium.org/241123002

git-svn-id: http://skia.googlecode.com/svn/trunk@14242 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/utils/android/ashmem.cpp b/src/utils/android/ashmem.cpp
index 461c062..1e512be 100644
--- a/src/utils/android/ashmem.cpp
+++ b/src/utils/android/ashmem.cpp
@@ -22,6 +22,8 @@
 
 #include <linux/ashmem.h>
 
+#include <SkTypes.h>  // SkASSERT
+
 #define ASHMEM_DEVICE   "/dev/ashmem"
 
 /*
@@ -66,13 +68,19 @@
 
 int ashmem_pin_region(int fd, size_t offset, size_t len)
 {
-    struct ashmem_pin pin = { offset, len };
+    // Skia only calls this when offset=len=0.
+    struct ashmem_pin pin = { static_cast<__u32>(offset),
+                              static_cast<__u32>(len) };
+    SkASSERT(pin.offset == offset && pin.len == len);
     return ioctl(fd, ASHMEM_PIN, &pin);
 }
 
 int ashmem_unpin_region(int fd, size_t offset, size_t len)
 {
-    struct ashmem_pin pin = { offset, len };
+    // Skia only calls this when offset=len=0.
+    struct ashmem_pin pin = { static_cast<__u32>(offset),
+                              static_cast<__u32>(len) };
+    SkASSERT(pin.offset == offset && pin.len == len);
     return ioctl(fd, ASHMEM_UNPIN, &pin);
 }