Fix gcc 4.6 compile issues; set but unused variable and pointer/FALSE fubar.

chrome/browser/chromeos/external_metrics_unittest.cc

Index: chrome/browser/chromeos/external_metrics_unittest.cc
diff --git a/chrome/browser/chromeos/external_metrics_unittest.cc b/chrome/browser/chromeos/external_metrics_unittest.cc
index 9f69b91253cd850322c06412412fb36c4cf698f9..8a6f91db554bec11fed3fe645ccadcf96001caaf 100644
--- a/chrome/browser/chromeos/external_metrics_unittest.cc
+++ b/chrome/browser/chromeos/external_metrics_unittest.cc
@@ -24,10 +24,11 @@ class ExternalMetricsTest : public testing::Test {
 static void SendMessage(const char* path, const char* name, const char* value) {
   int fd = open(path, O_CREAT | O_APPEND | O_WRONLY, 0666);
   int32 l = strlen(name) + strlen(value) + 2 + sizeof(l);
-  int num_bytes;
-  num_bytes = write(fd, &l, sizeof(l));
-  num_bytes = write(fd, name, strlen(name) + 1);
-  num_bytes = write(fd, value, strlen(value) + 1);
+  size_t num_bytes = 0;
+  num_bytes += write(fd, &l, sizeof(l));
+  num_bytes += write(fd, name, strlen(name) + 1);
+  num_bytes += write(fd, value, strlen(value) + 1);
+  EXPECT_EQ(num_bytes, sizeof(l) + strlen(name) + strlen(value) + 2);
   close(fd);
 }