Make all of our unit tests be PlatformTests to get an autorelease pool....

chrome/browser/cocoa/download_shelf_mac_unittest.mm

Index: chrome/browser/cocoa/download_shelf_mac_unittest.mm
===================================================================
--- chrome/browser/cocoa/download_shelf_mac_unittest.mm	(revision 24882)
+++ chrome/browser/cocoa/download_shelf_mac_unittest.mm	(working copy)
@@ -6,8 +6,8 @@
 #include "chrome/browser/cocoa/cocoa_test_helper.h"
 #include "chrome/browser/cocoa/download_shelf_mac.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#include "testing/platform_test.h"
 
-
 // A fake implementation of DownloadShelfController. It implements only the
 // methods that DownloadShelfMac call during the tests in this file. We get this
 // class into the DownloadShelfMac constructor by some questionable casting --
@@ -45,7 +45,7 @@
 
 namespace {
 
-class DownloadShelfMacTest : public testing::Test {
+class DownloadShelfMacTest : public PlatformTest {
 
   virtual void SetUp() {
     shelf_controller_.reset([[FakeDownloadShelfController alloc] init]);